USACO ORZ Time Limit: 5000/1500 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Problem Description Like everyone, cows enjoy variety. Their current fancy is new shapes for pastures. The old rectangular shapes are out of favor; new geom…
因为题中的操作是区间加法,所以满足前缀相减性. 而每一次查询的时候还是单点查询,所以直接用可持久化线段树维护差分数组,然后查一个前缀和就行了. code: #include <bits/stdc++.h> #define N 200004 #define LL long long #define setIO(s) freopen(s".in","r",stdin) using namespace std; int n,m,q,tot,rt[N]; LL…
就根据题目中给的约束条件建图就行了 需要注意的是,我们要做的是最长路,因为需要约束每个点都是大于0 那么可以建一个超级源指向所有点,超级源的dis是1,边长为0 那么这样做最长路就可以了 好了我们这么写完了,之后发现re了,然后改大了点数组发现tle了.... 然后我也不知道怎么改,超级源连接所有点的时候,是for i:=1 to n do 的,这 样建完图之后,再做spfa相当于直接将n-1的点放入队列中,然后我改了下 连接的时候for i:=n downto 1 do 那么相当于将1-n放入…
Burn the Linked Camp Time Limit: 2 Seconds Memory Limit: 65536 KB It is well known that, in the period of The Three Empires, Liu Bei, the emperor of the Shu Empire, was defeated by Lu Xun, a general of the Wu Empire. The defeat was due to Liu Be…
Yixght is a manager of the company called SzqNetwork(SN). Now she's very worried because she has just received a bad news which denotes that DxtNetwork(DN), the SN's business rival, intents to attack the network of SN. More unfortunately, the origina…
Code: #include<cstdio> #include<queue> #include<algorithm> using namespace std; const int N=500000+3; const int INF=-233333333+2; int head[N],to[N<<1],nex[N<<1],val[N<<1],d[N],inq[N]; queue<int>Q; int cnt,s,t,n; v…
题目链接:http://codeforces.com/problemset/problem/296/C 题意:给你n.m.k,表示n个数a[i],m个对数的操作,k个对操作的操作.m个操作:数a[l]到a[r]范围内都加上d:k个操作:操作m[l]到操作m[l]范围内都执行一次. 线段树套线段树,但是树状数组好写(区间更新单点查询.本质也是差分),附上学弟差分数组的写法. #include<bits/stdc++.h> #define ll long long using namespace…
题意: 给了由n个数组成的一个数列,然后给你各种区间的和是大于ci还是小于ci啥的,最后问你是否冲突. 思路: 差分约束水题,不过wa了两次,原因处理区间问题的细节马虎了,说下建图吧,这个题目给的是大于或者小于,不是大于等于啥的,其实这个好办,直接进行相应的+-1就能添加等于号了,然后进行关系转换 假如输入的是 a b str c b = a + b + 1 //一开始忘记了区间的这个处理方法忘记+1 那么if(str[0] == g) b - a > c b - a >…