CF449B CF450D http://codeforces.com/contest/450/problem/D http://codeforces.com/contest/449/problem/B Codeforces Round #257 (Div. 2) D Codeforces Round #257 (Div. 1) B D. Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megaby…

D. Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Jzzhu is the president of country A. There are n cities numbered from 1 to n in his country. City 1 is the capital of A.…

堆优化dijkstra,假设哪条铁路能够被更新,就把相应铁路删除. B. Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Jzzhu is the president of country A. There are n cities numbered from 1 to n in his co…

题目描述: Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Jzzhu is the president of country A. There are n cities numbered from 1 to n in his country. City 1 is the capital of…

CF449B Jzzhu and Cities 其实这一道题并不是很难,只是一个最短路而已,请继续看我的题解吧~(^▽^) AC代码: #include<bits/stdc++.h> #define maxn 3000005 #define pa pair<long long,long long> #define inf 1000000000000000000ll using namespace std; long long n,m,k; struct edge{ long lon…

D. Jzzhu and Cities time limit per test: 2 seconds memory limit per test: 256 megabytes input: standard input output: standard output Jzzhu is the president of country A. There are \(n\) cities numbered from \(1\) to \(n\) in his country. City \(1\)…

Jzzhu is the president of country A. There are n cities numbered from 1 to n in his country. City 1 is the capital of A. Also there are m roads connecting the cities. One can go from city ui to vi (and vise versa) using the i-th road, the length of t…

输入一个无向图<V,E>    V<=1e5, E<=3e5 现在另外给k条边(u=1,v=s[k],w=y[k]) 问在不影响从结点1出发到所有结点的最短路的前提下,最多可以删除k条边的多少条 跑最短路的时候维护或者统计就好了 一开始用spfa.然后TLE 45...好久没写  Dij+堆优化   ... p.s.优先队列默认大顶堆 Dij+堆优化   264ms #include <cstdio> #include <cstring> #include…

题意:n个城市,中间有m条道路(双向),再给出k条铁路,铁路直接从点1到点v,现在要拆掉一些铁路,在保证不影响每个点的最短距离(距离1)不变的情况下,问最多能删除多少条铁路 分析:先求一次最短路,铁路的权值大于该点最短距离的显然可以删去,否则将该条边加入图中,再求最短路,记录每个点的前一个点,然后又枚举铁路,已经删去的就不用处理了,如果铁路权值大于该点最短距离又可以删去,权值相等时,该点的前一个点如果不为1,则这个点可以由其他路到达,这条铁路又可以删去. 由于本题中边比较多,最多可以有8x10^…

#include<bits/stdc++.h> #define MAXN 100050 #define MAXM 900000 using namespace std; struct st { int id; long long dis; st(int a,long long b) { id=a; dis=b; } st(){}; }; struct edge{ bool im; int id; long long w; edge *next; }; edge *adj[MAXN]; edge…