杭电acm2124

贪心

#include <stdio.h>#include <algorithm>using namespace std;bool cmp(const int &a, const int &b) {return a > b;}int main() {int l, n, i, ans, ids, sum;int d[600];while(~scanf("%d%d", &l, &n)) {sum = 0;for(i=0; i<n; i++) {scanf("%d", &d[i]);sum += d[i];}if(sum < l) {printf("impossible\n");continue;}sort(d, d+n, cmp);ans = 0;ids = 0;while(l>0 && ids<n) {if(l>d[ids]) {l -= d[ids];ans ++;} else {ans ++;l = 0;}ids ++;}printf("%d\n", ans);}return 0;}