Submission #6919421

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Source Code Expand

// #pragma GCC target("avx2")  // CPU 処理並列化
// #pragma GCC optimize("O3")  // CPU 処理並列化
// #pragma GCC optimize("unroll-loops")  // 条件処理の呼び出しを減らす
#include<stdio.h>
#include<math.h>
#include<algorithm>
#include<queue>
#include<deque>
#include<stack>
#include<string>
#include<string.h>
#include<vector>
#include<set>
#include<map>
#include<bitset>
#include<stdlib.h>
#include<cassert>
#include<time.h>
#include<bitset>
#include<numeric>
using namespace std;
const long long mod=1000000007;
const long long inf=mod*mod;
const long long d2=(mod+1)/2;
const double EPS=1e-10;
const double INF=1e+10;
const double PI=acos(-1.0);
const int C_SIZE = 3121000;
long long fact[C_SIZE];
long long finv[C_SIZE];
long long inv[C_SIZE];
long long Comb(int a,int b){
 	if(a<b||b<0)return 0;
 	return fact[a]*finv[b]%mod*finv[a-b]%mod;
}
void init_C(int n){
	fact[0]=finv[0]=inv[1]=1;
	for(int i=2;i<n;i++){
		inv[i]=(mod-(mod/i)*inv[mod%i]%mod)%mod;
	}
	for(int i=1;i<n;i++){
		fact[i]=fact[i-1]*i%mod;
		finv[i]=finv[i-1]*inv[i]%mod;
	}
}
long long pw(long long a,long long b){
	if(a<0LL)return 0;
	if(b<0LL)return 0;
	long long ret=1;
	while(b){
		if(b%2)ret=ret*a%mod;
		a=a*a%mod;
		b/=2;
	}
	return ret;
}
int ABS(int a){return max(a,-a);}
long long ABS(long long a){return max(a,-a);}
double ABS(double a){return max(a,-a);}
int sig(double r) { return (r < -EPS) ? -1 : (r > +EPS) ? +1 : 0; }
// ここから編集しろ
vector<int>g[110000];
char in[110000];
int need[110000];
int dfs(int a,int b){
	int ret=0;
	if(in[a]=='W')ret=1;
	for(int i=0;i<g[a].size();i++){
		if(b==g[a][i])continue;
		ret|=dfs(g[a][i],a);
	}
	need[a]=ret;
	return ret;
}
int bes=0;
int dp[110000];
int dp2[110000];
int cost[110000];
void calc(int a,int b){
	int ji=0;
	pair<int,int> b1=make_pair(-10,-10);
	pair<int,int> b2=make_pair(-10,-10);
	pair<int,int> d1=make_pair(-10,-10);
	pair<int,int> d2=make_pair(-10,-10);
	
	//printf("%d %d\n",a,b);
	for(int i=0;i<g[a].size();i++){
		if(need[g[a][i]]){
			ji++;
			if(g[a][i]!=b){
				calc(g[a][i],a);
				cost[a]+=2;
				cost[a]+=cost[g[a][i]];
				if(dp[g[a][i]]>b1.first){
					b2=b1;b1=make_pair(dp[g[a][i]],i);
				}else if(dp[g[a][i]]>b2.first){
					b2=make_pair(dp[g[a][i]],i);
				}
				if(dp2[g[a][i]]>d1.first){
					d2=d1;d1=make_pair(dp2[g[a][i]],i);
				}else if(dp2[g[a][i]]>d2.first){
					d2=make_pair(dp2[g[a][i]],i);
				}
				
			}
		}
	}
	if(ji%2==0&&in[a]=='W')cost[a]++;
	if(ji%2&&in[a]=='B')cost[a]++;

	int f=0;
	if((ji%2==0&&in[a]=='W')||(ji%2&&in[a]=='B'))f++;
	else f--;
	if(b1.second!=d1.second){
		bes=max(bes,b1.first+d1.first+f);
	}else{
		bes=max(bes,b1.first+d2.first+f);
		bes=max(bes,b2.first+d1.first+f);
	}
	bes=max(bes,d1.first+f);
	bes=max(bes,b1.first);

	int c1=b1.first+1;
	if((ji%2==0&&in[a]=='W')||(ji%2&&in[a]=='B'))c1++;
	else c1--;
	int c2=1;
	if((ji%2==0&&in[a]=='W')||(ji%2&&in[a]=='B'))c2++;
	else c2--;
	dp[a]=max(c2,c1);

	int e1=d1.first+1;
	if((ji%2==0&&in[a]=='W')||(ji%2&&in[a]=='B'))e1++;
	else e1--;
	int e2=1;

	dp2[a]=max(e2,e1);


}
int main(){
	int a;scanf("%d",&a);
	for(int i=0;i<a-1;i++){
		int p,q;scanf("%d%d",&p,&q);
		p--;q--;
		g[p].push_back(q);
		g[q].push_back(p);
	}
	scanf("%s",in);
	for(int i=0;i<a;i++){
		if(in[i]=='W'){
			dfs(i,-1);
			break;
		}
	}
	int pr=-1;
	for(int i=0;i<a;i++){
		if(need[i]){
			pr=i;break;
		}
	}
	if(pr==-1){
		printf("0\n");return 0;
	}
	calc(pr,-1);
	int ret=cost[pr]-bes;
//	printf("%d %d\n",cost[pr],bes);
	printf("%d\n",ret);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:141:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  int a;scanf("%d",&a);
                      ^
./Main.cpp:143:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   int p,q;scanf("%d%d",&p,&q);
                              ^
./Main.cpp:148:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s",in);
                ^

Judge Result