标签：二分

Assemble

1
18 800
processor 3500_MHz 66 5
processor 4200_MHz 103 7
processor 5000_MHz 156 9
processor 6000_MHz 219 12
memory 1_GB 35 3
memory 2_GB 88 6
memory 4_GB 170 12
mainbord all_onboard 52 10
harddisk 250_GB 54 10
harddisk 500_FB 99 12
casing midi 36 10
monitor 17_inch 157 5
monitor 19_inch 175 7
monitor 20_inch 210 9
monitor 22_inch 293 12
mouse cordless_optical 18 12
mouse microsoft 30 9
keyboard office 4 10

9

题意：你要组装一台电脑，现在给你不同种类的不同品质与价钱的部件，你的任务就是在不超过预算的前提下，从每一种部件中挑选一件，并且输出抽出的部件中最大的品质。

对于这种有最大最小值的题，没有思路时，一般用二分；

代码：

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
const int M = 1e3+5;
using namespace std;

struct node
{
    char name[25], type[25];
    int price, quality;
}s[M];
int n, b;

bool jud(int x){
    int i, j, sum = 0, pos, Min;
    for(i = 0; i < n;)
    {
        pos = -1; Min = 0x7fffffff;
        for(j = i; j < n&&!strcmp(s[i].name, s[j].name); ++ j)
        {
            if(Min > s[j].price&&s[j].quality >= x)
            {
                Min = s[j].price; pos = j;
            }
        }
        if(pos == -1)
            return 0;
        sum += Min;
        i = j;
    }
    if(sum > b) return 0;
    return 1;
}

int f(int left, int right)
{

    while(left <= right)
    {
        int mid = (left+right)>>1;  
        if(jud(mid)) left = mid+1; //这里如果满足就让left = mid+1（因为是要求的最大值）
        else right = mid-1;
    }
    return right;
}

int main()
{
    int t;
    scanf("%d", &t);
    //printf("%d %d\n",Min, Max);
    while(t --)
    {
        scanf("%d%d", &n, &b);
        int Min = 0x7fffffff, Max = -0x7fffffff;
        for(int i = 0; i < n; ++ i)
        {
            scanf("%s %s %d %d", s[i].name, s[i].type, &s[i].price, &s[i].quality);  //这里的name与题意的type反了，不过不影响做题。。。
            Min = min(Min, s[i].quality);
            Max = max(Max, s[i].quality);
        }
        int ans = f(Min, Max);
        printf("%d\n", ans);
    }
    return 0;
}

Hdoj 2333 Assemble 【二分】

标签：二分

原文地址：http://blog.csdn.net/shengweisong/article/details/45276329