Problem 512

Sums of Totients of Powers — odd-totient prefix G(5e8).

Answer50660591862310323
Output50660591862310323
StatusPASS
Native helperno
Runtime110 ms
Peak memory28736 KB
Time complexityO(n) (estimated)
Space complexityO(n) (estimated)

Performance comparison

MetricOur solutionBest known
Time complexityO(n)O(n log log n)
Space complexityO(n)O(n)
ApproachFlow solutionSieve-based totient computation
VerdictOptimal

Flow source

# Project Euler 512
# Sums of Totients of Powers — odd-totient prefix G(5e8).

extern {
    function calloc(n: i64, size: i64) -> ptr<void>
    function free(p: ptr<void>) -> void
}

const CAP: i64 = 2097152
const TARGET: i64 = 500000000

function odd_part_sum(n0: i64) -> i64 {
    let mut n: i64 = n0
    let mut total: i64 = 0
    while n > 0 {
        let odd_count: i64 = (n + 1) / 2
        total = total + odd_count * odd_count
        n = n / 2
    }
    return total
}

function hslot(key: i64, keys: ptr<i64>, used: ptr<i8>) -> i64 {
    let mut h: i64 = key % CAP
    if h < 0 { h = h + CAP }
    while used[h] == 1 && keys[h] != key {
        h = h + 1
        if h == CAP { h = 0 }
    }
    return h
}

function odd_totient(n: i64, keys: ptr<i64>, vals: ptr<i64>, used: ptr<i8>) -> i64 {
    if n <= 0 { return 0 }
    let s: i64 = hslot(n, keys, used)
    if used[s] == 1 { return vals[s] }
    let mut total: i64 = odd_part_sum(n)
    let mut lo: i64 = 2
    while lo <= n {
        let q: i64 = n / lo
        let hi: i64 = n / q
        total = total - (hi - lo + 1) * odd_totient(q, keys, vals, used)
        lo = hi + 1
    }
    used[s] = 1
    keys[s] = n
    vals[s] = total
    return total
}

function main() -> i32 {
    let keys: ptr<i64> = calloc(CAP, 8)
    let vals: ptr<i64> = calloc(CAP, 8)
    let used: ptr<i8> = calloc(CAP, 1)
    if keys == null || vals == null || used == null { return 1 }
    let ans: i64 = odd_totient(TARGET, keys, vals, used)
    printf("%lld\n", ans)
    free(keys); free(vals); free(used)
    return 0
}

Generated C

#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Flow runtime helpers */
typedef struct flow_temp_node { struct flow_temp_node* next; } flow_temp_node;
static flow_temp_node* flow_temp_head = NULL;
static int flow_temp_atexit_set = 0;
__attribute__((unused)) static void flow_temp_free_all(void) {
    while (flow_temp_head) {
        flow_temp_node* n = flow_temp_head;
        flow_temp_head = n->next;
        free(n);
    }
}
__attribute__((unused)) static void* flow_temp_alloc(size_t nbytes) {
    flow_temp_node* node = (flow_temp_node*)malloc(sizeof(flow_temp_node) + nbytes);
    if (!node) return NULL;
    node->next = flow_temp_head;
    flow_temp_head = node;
    if (!flow_temp_atexit_set) {
        flow_temp_atexit_set = 1;
        atexit(flow_temp_free_all);
    }
    return (void*)(node + 1);
}
#ifndef FLOW_DIAG
#define FLOW_DIAG(msg) fprintf(stderr, "%s", (msg))
#endif
#ifndef FLOW_LOG
#define FLOW_LOG(fmt, ...) printf(fmt, __VA_ARGS__)
#endif
#ifndef FLOW_LOG_EMPTY
#define FLOW_LOG_EMPTY(fmt) printf(fmt)
#endif
static char* flow_strcat(const char* a, const char* b) {
    size_t la = strlen(a ? a : ""), lb = strlen(b ? b : "");
    char* r = (char*)flow_temp_alloc(la + lb + 1);
    if (!r) return NULL;
    if (la) memcpy(r, a, la);
    if (lb) memcpy(r + la, b, lb);
    r[la + lb] = '\0';
    return r;
}

#define __flow_in_arr(arr, val) __extension__ ({ \
    int _found = 0; \
    size_t _n = sizeof(arr)/sizeof((arr)[0]); \
    for (size_t _i = 0; _i < _n; _i++) { \
        if ((arr)[_i] == (val)) { _found = 1; break; } \
    } _found; })

/* Unified fault handler (MISRA #279) — override with -DFLOW_FAULT_HANDLER=fn */
#ifndef FLOW_FAULT_HANDLER
__attribute__((unused)) static inline void flow_fault_handler(const char* msg) {
    fprintf(stderr, "flow: %s\n", msg ? msg : "fault");
    abort();
#if defined(__GNUC__) || defined(__clang__)
    __builtin_unreachable();
#endif
}
#else
#define flow_fault_handler FLOW_FAULT_HANDLER
#endif
#define flow_div_by_zero_handler() flow_fault_handler("division by zero")
#define flow_shift_ub_handler() flow_fault_handler("invalid shift (amount out of range or left-shift of negative)")

#ifndef FLOW_CHECKED_DIV
#define FLOW_CHECKED_DIV(L, R) (((R) != 0) ? ((L) / (R)) : (flow_div_by_zero_handler(), (L) * 0))
#endif
#ifndef FLOW_CHECKED_MOD
#define FLOW_CHECKED_MOD(L, R) (((R) != 0) ? ((L) % (R)) : (flow_div_by_zero_handler(), (L) * 0))
#endif
#ifndef FLOW_CHECKED_SHL
#define FLOW_CHECKED_SHL(L, R) ((((R) >= 0) && ((unsigned long long)(R) < (sizeof(L) * 8ull)) && ((L) >= 0)) ? ((L) << (R)) : (flow_shift_ub_handler(), (L) * 0))
#endif
#ifndef FLOW_CHECKED_SHR
#define FLOW_CHECKED_SHR(L, R) ((((R) >= 0) && ((unsigned long long)(R) < (sizeof(L) * 8ull))) ? ((L) >> (R)) : (flow_shift_ub_handler(), (L) * 0))
#endif

#include <math.h>

void* _ui_state = NULL;

static inline float i32_to_f32(int32_t v) { return (float)v; }

/* Host stub for @gpu kernels (device codegen replaces this). */
static inline int32_t gpu_thread_id(void) { return 0; }

int64_t odd_part_sum_i64(int64_t n0);
int64_t hslot_i64_ptr_i64_ptr_i8(int64_t key, int64_t* keys, int8_t* used);
int64_t odd_totient_i64_ptr_i64_ptr_i64_ptr_i8(int64_t n, int64_t* keys, int64_t* vals, int8_t* used);
int32_t main(void);

static const int64_t CAP = 2097152;
static const int64_t TARGET = 500000000;



int64_t odd_part_sum_i64(int64_t n0) {
    int64_t n = n0;
    int64_t total = 0;
    while (n > 0) {
        int64_t odd_count = FLOW_CHECKED_DIV(((n + 1)), (2));
        total = (total + (odd_count * odd_count));
        n = FLOW_CHECKED_DIV((n), (2));
    }
    return total;
}

int64_t hslot_i64_ptr_i64_ptr_i8(int64_t key, int64_t* keys, int8_t* used) {
    int64_t h = FLOW_CHECKED_MOD((key), (CAP));
    if (h < 0) {
        h = (h + CAP);
    }
    while ((used[h] == 1 && keys[h] != key)) {
        h = (h + 1);
        if (h == CAP) {
            h = 0;
        }
    }
    return h;
}

int64_t odd_totient_i64_ptr_i64_ptr_i64_ptr_i8(int64_t n, int64_t* keys, int64_t* vals, int8_t* used) {
    if (n <= 0) {
        return 0;
    }
    int64_t s = hslot_i64_ptr_i64_ptr_i8(n, keys, used);
    if (used[s] == 1) {
        return vals[s];
    }
    int64_t total = odd_part_sum_i64(n);
    int64_t lo = 2;
    while (lo <= n) {
        int64_t q = FLOW_CHECKED_DIV((n), (lo));
        int64_t hi = FLOW_CHECKED_DIV((n), (q));
        total = (total - (((hi - lo) + 1) * odd_totient_i64_ptr_i64_ptr_i64_ptr_i8(q, keys, vals, used)));
        lo = (hi + 1);
    }
    used[s] = 1;
    keys[s] = n;
    vals[s] = total;
    return total;
}

int32_t main(void) {
    int64_t* keys = (int64_t*)(calloc(CAP, 8));
    int64_t* vals = (int64_t*)(calloc(CAP, 8));
    int8_t* used = (int8_t*)(calloc(CAP, 1));
    if (((keys == NULL || vals == NULL) || used == NULL)) {
        return 1;
    }
    int64_t ans = odd_totient_i64_ptr_i64_ptr_i64_ptr_i8(TARGET, keys, vals, used);
    printf("%lld\n", ans);
    free(keys);
    free(vals);
    free(used);
    return 0;
}

Generated MLIR

module {
  llvm.func @printf(!llvm.ptr, ...) -> i32
  llvm.mlir.global internal constant @str_0("%lld\n\00") {addr_space = 0 : i32} : !llvm.array<6 x i8>
  func.func private @calloc(i64, i64) -> !llvm.ptr
  func.func private @free(!llvm.ptr) -> ()
  // Constant: CAP
  llvm.mlir.global internal constant @CAP(2097152 : i64) : i64
  // Constant: TARGET
  llvm.mlir.global internal constant @TARGET(500000000 : i64) : i64
  func.func @odd_part_sum(%arg0: i64) -> i64 {
    %0 = llvm.mlir.constant(1 : i64) : i64
    %1 = llvm.alloca %0 x i64 : (i64) -> !llvm.ptr
    llvm.store %arg0, %1 : i64, !llvm.ptr
    %2 = arith.constant 0 : i32
    %3 = arith.extsi %2 : i32 to i64
    %4 = llvm.mlir.constant(1 : i64) : i64
    %5 = llvm.alloca %4 x i64 : (i64) -> !llvm.ptr
    llvm.store %3, %5 : i64, !llvm.ptr
    cf.br ^bb0
    ^bb0:
    %6 = llvm.load %1 : !llvm.ptr -> i64
    %7 = arith.constant 0 : i32
    %9 = arith.extsi %7 : i32 to i64
    %8 = arith.cmpi sgt, %6, %9 : i64
    cf.cond_br %8, ^bb1, ^bb2
    ^bb1:
      %10 = llvm.load %1 : !llvm.ptr -> i64
      %11 = arith.constant 1 : i32
      %13 = arith.extsi %11 : i32 to i64
      %12 = arith.addi %10, %13 : i64
      %14 = arith.constant 2 : i32
      %16 = arith.extsi %14 : i32 to i64
      %15 = arith.divsi %12, %16 : i64
      %17 = llvm.load %5 : !llvm.ptr -> i64
      %18 = arith.muli %15, %15 : i64
      %19 = arith.addi %17, %18 : i64
      llvm.store %19, %5 : i64, !llvm.ptr
      %20 = llvm.load %1 : !llvm.ptr -> i64
      %21 = arith.constant 2 : i32
      %23 = arith.extsi %21 : i32 to i64
      %22 = arith.divsi %20, %23 : i64
      llvm.store %22, %1 : i64, !llvm.ptr
      cf.br ^bb0
    ^bb2:
    %24 = llvm.load %5 : !llvm.ptr -> i64
    func.return %24 : i64
  }
  func.func @hslot(%arg0: i64, %arg1: !llvm.ptr, %arg2: !llvm.ptr) -> i64 {
    %25 = llvm.mlir.addressof @CAP : !llvm.ptr
    %26 = llvm.load %25 : !llvm.ptr -> i64
    %27 = arith.remsi %arg0, %26 : i64
    %28 = llvm.mlir.constant(1 : i64) : i64
    %29 = llvm.alloca %28 x i64 : (i64) -> !llvm.ptr
    llvm.store %27, %29 : i64, !llvm.ptr
    %30 = llvm.load %29 : !llvm.ptr -> i64
    %31 = arith.constant 0 : i32
    %33 = arith.extsi %31 : i32 to i64
    %32 = arith.cmpi slt, %30, %33 : i64
    cf.cond_br %32, ^bb3, ^bb4
    ^bb3:
      %34 = llvm.load %29 : !llvm.ptr -> i64
      %35 = llvm.mlir.addressof @CAP : !llvm.ptr
      %36 = llvm.load %35 : !llvm.ptr -> i64
      %37 = arith.addi %34, %36 : i64
      llvm.store %37, %29 : i64, !llvm.ptr
      cf.br ^bb5
    ^bb4:
      cf.br ^bb5
    ^bb5:
    cf.br ^bb6
    ^bb6:
    %39 = llvm.load %29 : !llvm.ptr -> i64
    %40 = llvm.getelementptr %arg2[%39] : (!llvm.ptr, i64) -> !llvm.ptr, i8
    %38 = llvm.load %40 : !llvm.ptr -> i8
    %41 = arith.constant 1 : i32
    %43 = arith.extsi %38 : i8 to i32
    %42 = arith.cmpi eq, %43, %41 : i32
    %44 = scf.if %42 -> (i1) {
      %46 = llvm.load %29 : !llvm.ptr -> i64
      %47 = llvm.getelementptr %arg1[%46] : (!llvm.ptr, i64) -> !llvm.ptr, i64
      %45 = llvm.load %47 : !llvm.ptr -> i64
      %48 = arith.cmpi ne, %45, %arg0 : i64
      scf.yield %48 : i1
    } else {
      %49 = arith.constant false
      scf.yield %49 : i1
    }
    cf.cond_br %44, ^bb7, ^bb8
    ^bb7:
      %50 = llvm.load %29 : !llvm.ptr -> i64
      %51 = arith.constant 1 : i32
      %53 = arith.extsi %51 : i32 to i64
      %52 = arith.addi %50, %53 : i64
      llvm.store %52, %29 : i64, !llvm.ptr
      %54 = llvm.load %29 : !llvm.ptr -> i64
      %55 = llvm.mlir.addressof @CAP : !llvm.ptr
      %56 = llvm.load %55 : !llvm.ptr -> i64
      %57 = arith.cmpi eq, %54, %56 : i64
      cf.cond_br %57, ^bb9, ^bb10
      ^bb9:
        %58 = arith.constant 0 : i32
        %59 = arith.extsi %58 : i32 to i64
        llvm.store %59, %29 : i64, !llvm.ptr
        cf.br ^bb11
      ^bb10:
        cf.br ^bb11
      ^bb11:
      cf.br ^bb6
    ^bb8:
    %60 = llvm.load %29 : !llvm.ptr -> i64
    func.return %60 : i64
  }
  func.func @odd_totient(%arg0: i64, %arg1: !llvm.ptr, %arg2: !llvm.ptr, %arg3: !llvm.ptr) -> i64 {
    %61 = arith.constant 0 : i32
    %63 = arith.extsi %61 : i32 to i64
    %62 = arith.cmpi sle, %arg0, %63 : i64
    cf.cond_br %62, ^bb12, ^bb13
    ^bb12:
      %64 = arith.constant 0 : i32
      %65 = arith.extsi %64 : i32 to i64
      func.return %65 : i64
    ^bb13:
      cf.br ^bb14
    ^bb14:
    %66 = func.call @hslot(%arg0, %arg1, %arg3) : (i64, !llvm.ptr, !llvm.ptr) -> i64
    %68 = llvm.getelementptr %arg3[%66] : (!llvm.ptr, i64) -> !llvm.ptr, i8
    %67 = llvm.load %68 : !llvm.ptr -> i8
    %69 = arith.constant 1 : i32
    %71 = arith.extsi %67 : i8 to i32
    %70 = arith.cmpi eq, %71, %69 : i32
    cf.cond_br %70, ^bb15, ^bb16
    ^bb15:
      %73 = llvm.getelementptr %arg2[%66] : (!llvm.ptr, i64) -> !llvm.ptr, i64
      %72 = llvm.load %73 : !llvm.ptr -> i64
      func.return %72 : i64
    ^bb16:
      cf.br ^bb17
    ^bb17:
    %74 = func.call @odd_part_sum(%arg0) : (i64) -> i64
    %75 = llvm.mlir.constant(1 : i64) : i64
    %76 = llvm.alloca %75 x i64 : (i64) -> !llvm.ptr
    llvm.store %74, %76 : i64, !llvm.ptr
    %77 = arith.constant 2 : i32
    %78 = arith.extsi %77 : i32 to i64
    %79 = llvm.mlir.constant(1 : i64) : i64
    %80 = llvm.alloca %79 x i64 : (i64) -> !llvm.ptr
    llvm.store %78, %80 : i64, !llvm.ptr
    cf.br ^bb18
    ^bb18:
    %81 = llvm.load %80 : !llvm.ptr -> i64
    %82 = arith.cmpi sle, %81, %arg0 : i64
    cf.cond_br %82, ^bb19, ^bb20
    ^bb19:
      %83 = llvm.load %80 : !llvm.ptr -> i64
      %84 = arith.divsi %arg0, %83 : i64
      %85 = arith.divsi %arg0, %84 : i64
      %86 = llvm.load %76 : !llvm.ptr -> i64
      %87 = llvm.load %80 : !llvm.ptr -> i64
      %88 = arith.subi %85, %87 : i64
      %89 = arith.constant 1 : i32
      %91 = arith.extsi %89 : i32 to i64
      %90 = arith.addi %88, %91 : i64
      %92 = func.call @odd_totient(%84, %arg1, %arg2, %arg3) : (i64, !llvm.ptr, !llvm.ptr, !llvm.ptr) -> i64
      %93 = arith.muli %90, %92 : i64
      %94 = arith.subi %86, %93 : i64
      llvm.store %94, %76 : i64, !llvm.ptr
      %95 = arith.constant 1 : i32
      %97 = arith.extsi %95 : i32 to i64
      %96 = arith.addi %85, %97 : i64
      llvm.store %96, %80 : i64, !llvm.ptr
      cf.br ^bb18
    ^bb20:
    %98 = arith.constant 1 : i32
    %99 = arith.trunci %98 : i32 to i8
    %100 = llvm.getelementptr %arg3[%66] : (!llvm.ptr, i64) -> !llvm.ptr, i8
    llvm.store %99, %100 : i8, !llvm.ptr
    %101 = llvm.getelementptr %arg1[%66] : (!llvm.ptr, i64) -> !llvm.ptr, i64
    llvm.store %arg0, %101 : i64, !llvm.ptr
    %102 = llvm.load %76 : !llvm.ptr -> i64
    %103 = llvm.getelementptr %arg2[%66] : (!llvm.ptr, i64) -> !llvm.ptr, i64
    llvm.store %102, %103 : i64, !llvm.ptr
    %104 = llvm.load %76 : !llvm.ptr -> i64
    func.return %104 : i64
  }
  func.func @main() -> i32 {
    %106 = llvm.mlir.addressof @CAP : !llvm.ptr
    %107 = llvm.load %106 : !llvm.ptr -> i64
    %108 = arith.constant 8 : i32
    %109 = arith.extsi %108 : i32 to i64
    %105 = func.call @calloc(%107, %109) : (i64, i64) -> !llvm.ptr
    %111 = llvm.mlir.addressof @CAP : !llvm.ptr
    %112 = llvm.load %111 : !llvm.ptr -> i64
    %113 = arith.constant 8 : i32
    %114 = arith.extsi %113 : i32 to i64
    %110 = func.call @calloc(%112, %114) : (i64, i64) -> !llvm.ptr
    %116 = llvm.mlir.addressof @CAP : !llvm.ptr
    %117 = llvm.load %116 : !llvm.ptr -> i64
    %118 = arith.constant 1 : i32
    %119 = arith.extsi %118 : i32 to i64
    %115 = func.call @calloc(%117, %119) : (i64, i64) -> !llvm.ptr
    %120 = llvm.mlir.zero : !llvm.ptr
    %121 = llvm.icmp "eq" %105, %120 : !llvm.ptr
    %122 = scf.if %121 -> (i1) {
      %123 = arith.constant true
      scf.yield %123 : i1
    } else {
      %124 = llvm.mlir.zero : !llvm.ptr
      %125 = llvm.icmp "eq" %110, %124 : !llvm.ptr
      scf.yield %125 : i1
    }
    %126 = scf.if %122 -> (i1) {
      %127 = arith.constant true
      scf.yield %127 : i1
    } else {
      %128 = llvm.mlir.zero : !llvm.ptr
      %129 = llvm.icmp "eq" %115, %128 : !llvm.ptr
      scf.yield %129 : i1
    }
    cf.cond_br %126, ^bb21, ^bb22
    ^bb21:
      %130 = arith.constant 1 : i32
      func.return %130 : i32
    ^bb22:
      cf.br ^bb23
    ^bb23:
    %132 = llvm.mlir.addressof @TARGET : !llvm.ptr
    %133 = llvm.load %132 : !llvm.ptr -> i64
    %131 = func.call @odd_totient(%133, %105, %110, %115) : (i64, !llvm.ptr, !llvm.ptr, !llvm.ptr) -> i64
    %134 = llvm.mlir.addressof @str_0 : !llvm.ptr
    %135 = llvm.call @printf(%134, %131) vararg(!llvm.func<i32 (ptr, ...)>) : (!llvm.ptr, i64) -> i32
    func.call @free(%105) : (!llvm.ptr) -> ()
    func.call @free(%110) : (!llvm.ptr) -> ()
    func.call @free(%115) : (!llvm.ptr) -> ()
    %139 = arith.constant 0 : i32
    func.return %139 : i32
  }
}