代码

#define ful 255
int t0[ful + 1], t1[ful + 1], t2[ful + 1], t3[ful + 1];
unsigned *b = new unsigned[100000000];
void sort(unsigned *a, int n) {
    int i;
    for (i = 0; i < n; i++) ++t0[a[i] & ful], ++t1[a[i] >> 8 & ful], ++t2[a[i] >> 16 & ful], ++t3[a[i] >> 24];
    for (i = 1; i <= ful; i++) t0[i] += t0[i - 1], t1[i] += t1[i - 1], t2[i] += t2[i - 1], t3[i] += t3[i - 1];
    for (i = n - 1; ~i; i--) b[--t0[a[i] & ful]] = a[i];
    for (i = n - 1; ~i; i--) a[--t1[a[i] >> 8 & ful]] = b[i];
    for (i = n - 1; ~i; i--) b[--t2[a[i] >> 16 & ful]] = a[i];
    for (i = n - 1; ~i; i--) a[--t3[a[i] >> 24]] = b[i];
}

评测结果