AtCoder Grand Contest 010

Submission #1356518

Source codeソースコード

// Copyright (C) 2017 __debug.

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; version 3

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; If not, see <http://www.gnu.org/licenses/>.


#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/priority_queue.hpp>

#define x first
#define y second
#define MP std::make_pair
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()
#define DEBUG(...) fprintf(stderr, __VA_ARGS__)
#ifdef __linux__
#define getchar getchar_unlocked
#define putchar putchar_unlocked
#endif

using std::pair;
using std::vector;
using std::string;

typedef long long LL;
typedef pair<int, int> Pii;

const int oo = 0x3f3f3f3f;

template<typename T> inline bool chkmax(T &a, T b) { return a < b ? a = b, true : false; }
template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, true : false; }
string procStatus()
{
    std::ifstream t("/proc/self/status");
    return string(std::istreambuf_iterator<char>(t), std::istreambuf_iterator<char>());
}
template<typename T> T read(T &x)
{
    int f = 1;
    char ch = getchar();
    for (; !isdigit(ch); ch = getchar())
        f = (ch == '-' ? -1 : 1);
    for (x = 0; isdigit(ch); ch = getchar())
        x = 10 * x + ch - '0';
    return x *= f;
}
template<typename T> void write(T x)
{
    if (x == 0) {
        putchar('0');
        return;
    }
    if (x < 0) {
        putchar('-');
        x = -x;
    }
    static char s[20];
    int top = 0;
    for (; x; x /= 10)
        s[++top] = x % 10 + '0';
    while (top)
        putchar(s[top--]);
}
// EOT

const int MAXN = 1e5 + 5;

struct Edge {
    int v, next;
    Edge() { }
    Edge(int v_, int next_): v(v_), next(next_) { }
};

int N;
LL A[MAXN];
int tote, head[MAXN];
Edge edge[MAXN * 2 + 5];
int deg[MAXN];

inline void addEdge(int u, int v)
{
    edge[++tote] = Edge(v, head[u]);
    head[u] = tote;
}

void input()
{
    read(N);
    for (int i = 1; i <= N; ++i) {
        read(A[i]);
    }
    for (int i = 1; i < N; ++i) {
        int u, v;
        read(u); read(v);
        addEdge(u, v);
        addEdge(v, u);
        ++deg[u]; ++deg[v];
    }
}

LL dfs(int u, int f)
{
    if (deg[u] == 1)
        return A[u];
    LL sum = 0;
    LL max = 0;
    for (int i = head[u]; i; i = edge[i].next) {
        int v = edge[i].v;
        if (v == f) continue;
        LL cur = dfs(v, u);
        sum += cur;
        chkmax(max, cur);
    }
    LL fe = 2 * A[u] - sum;
    sum += fe;
    chkmax(max, fe);
    if (fe < 0 || sum % 2 != 0 || (max > sum / 2)) {
        puts("NO");
        exit(0);
    }
    return fe;
}

void solve()
{
    if (N == 2) {
        puts(A[1] == A[2] ? "YES" : "NO");
        return;
    }
    int rt = 0;
    for (int i = 1; i <= N; ++i) {
        if (deg[i] != 1) {
            rt = i;
            break;
        }
    }
    LL left = dfs(rt, 0);
    puts(left == 0 ? "YES" : "NO");
}

int main()
{
#ifdef __DEBUG
    freopen("C.in", "r", stdin);
    freopen("C.out", "w", stdout);
#endif

    input();
    solve();

    return 0;
}

// 离离原上草,一岁一枯荣。
//     -- 白居易《草 / 赋得古原草送别》

Submission

Task問題 C - Cleaning
User nameユーザ名 Ivlleio
Created time投稿日時
Language言語 C++14 (GCC 5.4.1)
Status状態 AC
Score得点 700
Source lengthソースコード長 3735 Byte
File nameファイル名
Exec time実行時間 13 ms
Memory usageメモリ使用量 8704 KB

Test case

Set

Set name Score得点 / Max score Cases
Sample - sample1.txt,sample2.txt,sample3.txt
All 700 / 700 sample1.txt,sample2.txt,sample3.txt,in1.txt,in10.txt,in11.txt,in12.txt,in13.txt,in14.txt,in15.txt,in16.txt,in17.txt,in18.txt,in19.txt,in2.txt,in20.txt,in21.txt,in22.txt,in23.txt,in24.txt,in25.txt,in26.txt,in27.txt,in28.txt,in29.txt,in3.txt,in30.txt,in31.txt,in32.txt,in33.txt,in34.txt,in35.txt,in36.txt,in37.txt,in38.txt,in39.txt,in4.txt,in40.txt,in41.txt,in42.txt,in43.txt,in44.txt,in45.txt,in5.txt,in6.txt,in7.txt,in8.txt,in9.txt,sample1.txt,sample2.txt,sample3.txt

Test case

Case name Status状態 Exec time実行時間 Memory usageメモリ使用量
in1.txt AC 12 ms 3328 KB
in10.txt AC 12 ms 3328 KB
in11.txt AC 13 ms 7680 KB
in12.txt AC 13 ms 7680 KB
in13.txt AC 12 ms 8704 KB
in14.txt AC 12 ms 7936 KB
in15.txt AC 1 ms 256 KB
in16.txt AC 1 ms 256 KB
in17.txt AC 1 ms 256 KB
in18.txt AC 1 ms 256 KB
in19.txt AC 10 ms 3328 KB
in2.txt AC 12 ms 3328 KB
in20.txt AC 9 ms 3328 KB
in21.txt AC 9 ms 3328 KB
in22.txt AC 9 ms 3328 KB
in23.txt AC 9 ms 3328 KB
in24.txt AC 10 ms 3328 KB
in25.txt AC 1 ms 256 KB
in26.txt AC 9 ms 3328 KB
in27.txt AC 9 ms 3328 KB
in28.txt AC 1 ms 256 KB
in29.txt AC 7 ms 3328 KB
in3.txt AC 12 ms 3328 KB
in30.txt AC 1 ms 256 KB
in31.txt AC 9 ms 3328 KB
in32.txt AC 11 ms 3328 KB
in33.txt AC 12 ms 3328 KB
in34.txt AC 12 ms 3328 KB
in35.txt AC 12 ms 3328 KB
in36.txt AC 12 ms 3328 KB
in37.txt AC 1 ms 256 KB
in38.txt AC 9 ms 3328 KB
in39.txt AC 9 ms 3328 KB
in4.txt AC 12 ms 3328 KB
in40.txt AC 11 ms 3328 KB
in41.txt AC 10 ms 3328 KB
in42.txt AC 12 ms 3328 KB
in43.txt AC 10 ms 3328 KB
in44.txt AC 12 ms 3328 KB
in45.txt AC 12 ms 3328 KB
in5.txt AC 12 ms 3328 KB
in6.txt AC 12 ms 3328 KB
in7.txt AC 10 ms 3072 KB
in8.txt AC 4 ms 1024 KB
in9.txt AC 12 ms 3328 KB
sample1.txt AC 1 ms 256 KB
sample2.txt AC 1 ms 256 KB
sample3.txt AC 1 ms 256 KB