提出 #8537365

---

ソースコード 拡げる

#include<bits/stdc++.h>
#define fo(i, x, y) for(int i = x, B = y; i <= B; i ++)
#define ff(i, x, y) for(int i = x, B = y; i <  B; i ++)
#define fd(i, x, y) for(int i = x, B = y; i >= B; i --)
#define ll long long
#define pp printf
#define hh pp("\n")
using namespace std;

const int N = 1e5 + 5;

int n, x, y;
int fi[N], to[N * 2], nt[N * 2], tot = 1;

void link(int x, int y) {
	nt[++ tot] = fi[x], to[tot] = y, fi[x] = tot;
}

char str[N]; int cr[N];

int d[N], d0, r[N], ky[N];

void Init() {
	scanf("%d", &n);
	fo(i, 1, n - 1) {
		scanf("%d %d", &x, &y);
		r[x] ++, r[y] ++;
		link(x, y); link(y, x);
	}
	scanf("%s", str + 1);
	fo(i, 1, n) cr[i] = str[i] == 'B' ? 1 : 0;
}

void build() {
	fo(i, 1, n) ky[i] = 1;
	fo(i, 1, n) if(r[i] == 1 && cr[i] == 1)
		d[++ d0] = i;
	for(int i = 1; i <= d0; i ++) {
		int x = d[i]; ky[x] = 0;
		for(int j = fi[x]; j; j = nt[j]) {
			int y = to[j];
			if(-- r[y] == 1 && cr[y] == 1) d[++ d0] = y;
		}
	} 
}

int rt, fa[N], c[N];
int sum, ans;
int s[N], f[N], g[N];

void dg(int x) {
	c[x] = !((r[x] & 1) ^ cr[x]);
	d[x] = (c[x] ? 1 : -1) + 1;
	s[x] = s[fa[x]] + d[x];
	sum += c[x];
	f[x] = s[x], g[x] = s[x] - d[x];
	for(int i = fi[x]; i; i = nt[i]) if(to[i] != fa[x] && ky[to[i]]) {
		int y = to[i];
		fa[y] = x;
		dg(y);
		ans = max(ans, max(f[x] + g[y], g[x] + f[y]) - 2 * s[x] + d[x]);
		f[x] = max(f[x], f[y]);
		g[x] = max(g[x], g[y]);
	}
}

void work() {
	sum = -2;
	fo(i, 1, n) if(ky[i])
		rt = i, sum += 2;
	if(!rt) {
		pp("0\n");
		exit(0);
	}
	dg(rt);
}
int main() {
	Init();
	build();
	work();
	pp("%d\n", sum - ans);
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘void Init()’:
./Main.cpp:24:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
./Main.cpp:26:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &x, &y);
                         ^
./Main.cpp:30:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s", str + 1);
                      ^

ジャッジ結果