B表示完全看不懂。。就不弄了。。
E字符串先不管了。到时候系统学下字符串再处理
A
#include <map> #include <set> #include <list> #include <cmath> #include <ctime> #include <deque> #include <stack> #include <queue> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <climits> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define LL long long #define PI 3.1415926535897932626 using namespace std; int gcd(int a, int b) {return a % b == 0 ? b : gcd(b, a % b);} int src[13]; int main() { int K; scanf("%d",&K); for (int i = 0; i < 12; i++) scanf("%d",&src[i]); sort(src,src+12); int ans = 0 ,sum = 0, cas = 11; while (true) { if (sum >= K) break; if (ans == 13) break; sum += src[cas]; cas--; ans++; } if (ans == 13) puts("-1"); else printf("%d\n",ans); return 0; }