Submission #1610701

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Source Code Expand

#ifdef DEBUG
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <iostream>
#include <cassert>
#include <sstream>
#include <fstream>
#include <functional>
#include <set>
#include <bitset>
#include <string>
#include <utility>
#include <queue>
#include <deque>
#include <vector>
#include <map>
#else
#include <bits/stdc++.h>
#endif

#ifdef DEBUG
#define debug(...) fprintf(stderr, __VA_ARGS__)
#else
#define debug(...)
#endif

#define rep(i, n) for (int i = 0, i##_end_ = (n); i < i##_end_; ++i)
#define per(i, n) for (int i = (n) - 1; i >= 0; --i)
#define forn(i, l, r) for (int i = (l), i##_end_ = (r); i <= i##_end_; ++i)
#define nrof(i, r, l) for (int i = (r), i##_end_ = (l); i >= i##_end_; --i)
#define X first
#define Y second
#define mp make_pair
#define pb push_back
#define SZ(x) (int)((x).size())
#define ALL(x) (x).begin(), (x).end()

using namespace std;

typedef vector<int> vi;

typedef pair<int, int> pii;

typedef long long LL;

template<typename T> inline bool chkmax(T &x, const T &y) {
	return x < y ? x = y, 1 : 0;
}

#ifdef DEBUG
char *input_file, *output_file;
#endif

struct IO {
	static const int maxn = (1 << 25) + 10;

	char a[maxn], *s, b[maxn], *t;

	void INPUT() {
		s = a;
		t = b;
		#ifdef DEBUG
		FILE *f = fopen(input_file, "r");
		a[fread(a, 1, sizeof a, f)] = 0;
		#else
		a[fread(a, 1, sizeof a, stdin)] = 0;
		#endif
	}

	void OUTPUT() {
#ifdef DEBUG
		FILE *f = fopen(output_file, "w");
		fwrite(b, 1, t - b, f);
#else
		fwrite(b, 1, t - b, stdout);
#endif
	}

	operator int() {
		int x = 0;
		while(*s != '-' && (*s < '0' || *s > '9')) {
			++s;
		}
		bool f = 0;
		if(*s == '-') {
			f = 1;
			++s;
		}
		while(*s >= '0' && *s <= '9') {
			(x *= 10) += *s - '0';
			++s;
		}
		if(f) {
			x = -x;
		}
		return x;
	}

	operator LL() {
		LL x = 0;
		while(*s != '-' && (*s < '0' || *s > '9')) {
			++s;
		}
		bool f = 0;
		if(*s == '-') {
			f = 1;
			++s;
		}
		while(*s >= '0' && *s <= '9') {
			(x *= 10) += *s - '0';
			++s;
		}
		if(f) {
			x = -x;
		}
		return x;
	}

	operator char() {
		while(*s <= 32) {
			++s;
		}
		char ret = *s;
		++s;
		return ret;
	}

	inline void out(int x) {
		if(!x) {
			*t++ = '0';
			return;
		}
		if(x < 0) {
			*t++ = '-';
			x = -x;
		}
		static char c[20], *i;
		i = c;
		while(x) {
			int y = x / 10;
			*i++ = x - y * 10 + '0';
			x = y;
		}
		while(i != c) {
			*t++ = *--i;
		}
		return;
	}

	inline void out(int x, char C) {
		if(!x) {
			*t++ = '0';
			*t++ = C;
			return;
		}
		if(x < 0) {
			*t++ = '-';
			x = -x;
		}
		static char c[20], *i;
		i = c;
		while(x) {
			int y = x / 10;
			*i++ = x - y * 10 + '0';
			x = y;
		}
		while(i != c) {
			*t++ = *--i;
		}
		*t++ = C;
		return;
	}

	inline void out(LL x) {
		if(!x) {
			*t++ = '0';
			return;
		}
		if(x < 0) {
			*t++ = '-';
			x = -x;
		}
		static char c[20], *i;
		i = c;
		while(x) {
			LL y = x / 10;
			*i++ = x - y * 10 + '0';
			x = y;
		}
		while(i != c) {
			*t++ = *--i;
		}
		return;
	}

	inline void out(LL x, char C) {
		if(!x) {
			*t++ = '0';
			*t++ = C;
			return;
		}
		if(x < 0) {
			*t++ = '-';
			x = -x;
		}
		static char c[20], *i;
		i = c;
		while(x) {
			LL y = x / 10;
			*i++ = x - y * 10 + '0';
			x = y;
		}
		while(i != c) {
			*t++ = *--i;
		}
		*t++ = C;
		return;
	}

	inline void out(char c) {
		*t++ = c;
		return;
	}

	inline void out(char *s) {
		while(*s >= ' ') {
			*t++ = *s++;
		}
		return;
	}
}io;

void Main();

int main(int argc, char *argv[]) {
#ifdef DEBUG
	input_file = argv[1];
	output_file = argv[2];
#endif
	io.INPUT();
	Main();
	io.OUTPUT();
	return 0;
}

//---------------------------------------------------------------------------------------head---------------------------------------------------------------------------------------

const int maxn = 1e5 + 100;

int n, m;
map<int, int> e[maxn];
int par[maxn];
queue<pii> q;

int F(int u) {
	return par[u] == u ? u : par[u] = F(par[u]);
}

void Main() {
	n = io;
	forn(i, 1, n) {
		par[i] = i;
	}
	rep(i, n - 1 << 1) {
		int u = io, v = io;
		++e[u][v];
		++e[v][u];
		q.push(mp(u, v));
	}
	while(!q.empty()) {
		int u, v;
		tie(u, v) = q.front();
		u = F(u);
		v = F(v);
		q.pop();
		if(u == v || e[u].find(v) == e[u].end() || e[v].find(u) == e[v].end()) {
			continue;
		}
		if(e[u][v] > 2) {
			io.out("NO\n");
			return;
		}
		if(e[u][v] < 2) {
			continue;
		}
		if(SZ(e[v]) > SZ(e[u])) {
			swap(u, v);
		}
		par[v] = u;
		e[u].erase(v);
		for (auto it: e[v]) {
			int w = it.X, x = it.Y;
			if(w == u) {
				continue;
			}
			e[u][w] += x;
			e[w][u] += x;
			q.push(mp(u, w));
			e[w].erase(v);
		}
		e[v].clear();
		++m;
	}
	if(m == n - 1) {
		io.out("YES\n");
	}
	else {
		io.out("NO\n");
	}
	return;
}

Submission Info

Compile Error

./Main.cpp: In function ‘void Main()’:
./Main.cpp:282:17: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings]
    io.out("NO\n");
                 ^
./Main.cpp:307:17: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings]
   io.out("YES\n");
                 ^
./Main.cpp:310:16: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings]
   io.out("NO\n");
                ^

Judge Result