Submission #1868339

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=4e5+10;
int n,w[N],head[N],nxt[N];
void add(int f,int t){
	static int cnt=0;
	w[++cnt]=t;
	nxt[cnt]=head[f];
	head[f]=cnt;
}
char tp[N];
long long ans;
int mp[N],cp[N],up[N];
void dfs(int x,int fa){
    for (int i=head[x];i;i=nxt[i]){
        int v=w[i];
        if (v==fa) continue;
        dfs(v,x);
        if (up[v]>up[mp[x]]) cp[x]=mp[x],mp[x]=v;else
        if (up[v]>up[cp[x]]) cp[x]=v;
    }
    up[x]=up[mp[x]]+1;
}
int Max[N];
void DFS(int x,int fa){
    Max[x]=up[x];
    for (int i=head[x];i;i=nxt[i]){
        int v=w[i];
        if (v==fa) continue;
        up[x]=up[v==mp[x]?cp[x]:mp[x]]+1;
        //一个深度为up[x],另一个深度为up[v]
        ans+=min(up[v]+1,up[x]);
        if (up[x]>up[mp[v]]) cp[v]=mp[v],mp[v]=x;else
        if (up[x]>up[cp[v]]) cp[v]=x;
        up[v]=up[mp[v]]+1;
        DFS(v,x);
        up[v]=up[x==mp[v]?cp[v]:mp[v]]+1;
        up[x]=up[mp[x]]+1;
    }
}
int main()
{
	scanf("%d",&n);
	for (int i=1;i<n;i++){
		int u,v;
		scanf("%d%d",&u,&v);
		add(u,v);add(v,u);
	}
	scanf("%s",tp+1);
	dfs(1,0);DFS(1,0);
	printf("%lld\n",ans+Max[1]);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:44:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:47:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&u,&v);
                      ^
./Main.cpp:50:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",tp+1);
                  ^

Judge Result