#include 

#define N 9 
int q[N] = {0};
int not_end = 1;
int trace = 0;
int cnt = 0;
int sum = 0;

void print_q() {
int i;

for (i=0; i=0 && j>=0; i--,j--) {
if (q[i] == j) return 0;
    }

//right-up  for (i=m-1,j=n+1; i>=0 && j= 0) {
if (q[trace] < N-1) {
            q[trace]+=1;
break;
        }

        q[trace]= 0;
        trace--;
    }

if ( trace < 0) {
        not_end= 0;
    }else {
int i = trace + 1;
while (i < N) {
            q[i]= 0;
            i++;
        }
    }

return;
}

int main(int argc, char* argv[]) {
while (not_end) {
int i;

for (trace; trace

再次执行就好看多了

CNT: 352, times: 72378

real    0m0.007s
user    0m0.004s
sys    0m0.000s

CNT: 14772512, times: 842815472

real    12m26.208s
user    12m25.835s
sys    0m0.028s