代码

typedef unsigned int uint;

void sort(uint *a, int n) {
	uint t[100000000];
	register uint b0[256], b1[256], b2[256], b3[256], *ed = a + n;
	for (register uint *i = a; i != ed; i++) {
		b0[*i & 255]++, b1[(*i >> 8) & 255]++, b2[(*i >> 16) & 255]++, b3[*i >> 24]++;
	}
	for (register int i = 1; i < 256; i++) {
		b0[i] += b0[i - 1], b1[i] += b1[i - 1], b2[i] += b2[i - 1], b3[i] += b3[i - 1];
	}
	for (register uint *i = a + n - 1; i != a; i--) {
		t[--b0[*i & 255]] = *i;
	}
	for (register uint *i = t + n - 1; i != t; i--) {
		a[--b1[(*i >> 8) & 255]] = *i;
	}
	for (register uint *i = a + n - 1; i != a; i--) {
		t[--b2[(*i >> 16) & 255]] = *i;
	}
	for (register uint *i = t + n - 1; i != t; i--) {
		a[--b3[*i >> 24]] = *i;
	}
}

评测结果