LA3971-Assemble（贪心+二分）

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题目链接：

http://acm.hust.edu.cn/vjudge/problem/13338

思路：

使最小值最大，只需要对目标进行二分，并且judge一下是否合法，在judge函数里面，用贪心思想，对于满足条件的，选择价值最低的

代码

#include <iostream>#include <cstring>#include <stack>#include <vector>#include <set>#include <map>#include <cmath>#include <queue>#include <sstream>#include <iomanip>#include <fstream>#include <cstdio>#include <cstdlib>#include <climits>#include <deque>#include <bitset>#include <algorithm>using namespace std;#define PI acos(-1.0)#define LL long long#define PII pair<int, int>#define PLL pair<LL, LL>#define mp make_pair#define IN freopen("in.txt", "r", stdin)#define OUT freopen("out.txt", "wb", stdout)#define scan(x) scanf("%d", &x)#define scan2(x, y) scanf("%d%d", &x, &y)#define scan3(x, y, z) scanf("%d%d%d", &x, &y, &z)#define sqr(x) (x) * (x)#define pr(x) cout << #x << " = " << x << endl#define lc o << 1#define rc o << 1 | 1#define pl() cout << endlconst int maxn = 1000 + 5;const int maxq = 1000000000;int n, bg, cnt;map<string, int> id;vector<PII> v[maxn];int getid(string s) {    if (!id.count(s)) id[s] = cnt++;    return id[s];}bool judge(int x) {    int mon = 0;    for (int i = 0; i < cnt; i++) {        int t = bg + 1;        int _s = v[i].size();        for (int j = 0; j < _s; j++) {            if (v[i][j].second >= x) t = min(t, v[i][j].first);        }        if (t == bg + 1) return false;        mon += t;        if (mon > bg) return false;    }    return true;}void init() {    id.clear();    for (int i = 0; i <= n; i++) v[i].clear();}int main() {    int x, y, T;    scan(T);    while (T--) {        cnt = 0;        scan2(n, bg);        init();        for (int i = 0; i < n; i++) {            char s1[30], s2[30];            scanf("%s %s %d %d", s1, s2, &x, &y);            v[getid(s1)].push_back(mp(x, y));                    }        int L = 0, R = maxq, M;        while (L < R) {            M = L + (R - L + 1) / 2;            if (judge(M)) L = M;            else R = M - 1;        }        printf("%d\n", L);    }    return 0;}

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