zoj 2520 Amicable Pairs

#include <iostream>#include <cstdio>using namespace std;const int maxn = 210000;int tb[maxn];int ans[85][2];void init(){for(int i = 1; i < maxn; ++i)tb[i] = 1;for(int i = 2; i <= maxn / 2; ++i){for(int j = i + i; j< maxn; j += i){tb[j] += i;}}int idx = 1;for(int i = 220; i < maxn; ++i){if( i < tb[i] && tb[i] < maxn&& tb[tb[i]] == i){ans[idx][0] = i;ans[idx++][1] = tb[i];}}}int main(){init();int k;while(scanf("%d", &k) == 1){printf("%d %dn", ans[k][0], ans[k][1]);}return 0;}