题目大意:现有n个通讯点, 要从n家通讯商那,每个通讯商中选出一个设备, 要求所选设备的带宽中最小的做为最小带宽B, 总价格为P, 现在要求求出B/P的值最大
思路:依次枚举B能到的值
code:
#include <stdio.h> #include <algorithm> #define inf 0x7fffffff using namespace std; struct node { int w, v; }p[102][102]; int main() { // freopen("input.txt", "r", stdin); int i = 0, j = 0, k = 0, n = 0, t = 0, price = 0, max = 0, min = inf; int m[102]; double ans = 0; scanf("%d", &t); while(t--) { scanf("%d", &n); min = inf; max = 0; for(i = 0; i<n; i++) { scanf("%d", &m[i]); for(j = 0; j<m[i]; j++) { scanf("%d %d", &p[i][j].w, &p[i][j].v); if(min>p[i][j].w) min = p[i][j].w; if(max<p[i][j].w) max = p[i][j].w; } } int flag = 0; ans = -1; for(i = min; i<=max; i++) { double sum = 0; for(k = 0; k<n; k++) { price = inf; flag = 0; for(j = 0; j<m[k] ; j++) { if(p[k][j].w>=i && price>p[k][j].v) { flag = 1; price = p[k][j].v; } } if(!flag) break;//在这组中没有可选的 sum += price; } if(!flag) break; if(ans<(double)i/sum) ans = (double)i/sum; } printf("%.3lf\n", ans); } return 0; }