LA 3971 二分

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直接二分搜品质因子
AC代码如下：
#include <cstring>#include <cstdio>#include <algorithm>#include <iostream>#include <map>#include <string>#include <vector>using namespace std;#define MAX 0x3f3f3f3fint N, B;map<string,int> id;vector<int> price[1100], para[1100];int cnt, L, R;bool judge( int M ){    int sum = 0;    for( int i = 1; i <= cnt; i++ ){        int temp = MAX;        for( int j = 0; j < price[i].size(); j++ ){            if( para[i][j] >= M ){                temp = min( temp, price[i][j] );            }        }        sum += temp;        if( sum > B ){            return false;        }    }    return true;}int main(){    int T;    scanf( "%d", &T );    while( T-- ){        scanf( "%d%d", &N, &B );        id.clear();        for( int i = 0; i < 1100; i++ ){            price[i].clear();            para[i].clear();        }        cnt = 0;        R = 0;        for( int i = 0; i < N; i++ ){            string temp1, temp2;            int temp3, temp4;            cin >> temp1 >> temp2 >> temp3 >> temp4;            R = max( R, temp4 );            if( id.find( temp1 ) != id.end() ){                price[id[temp1]].push_back( temp3 );                para[id[temp1]].push_back( temp4 );            }else{                id[temp1] = ++cnt;                price[id[temp1]].push_back( temp3 );                para[id[temp1]].push_back( temp4 );            }        }        L = 0;        while( L < R ){            int M = L + ( R - L + 1 ) / 2;            if( judge( M ) ){                L = M;            }else{                R = M - 1;            }        }        cout << L << endl;    }    return 0;}
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