AtCoder Beginner Contest 088

A

模拟。

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#include <iostream>
    using namespace std;
    int main()
    {
        int n,a;
        while(cin>>n>>a){
            int s=n%500;
            if(s<=a){
                cout<<"Yes"<<endl;
            }
            else cout<<"No"<<endl;
        }
        return 0;
    }

B

猜一下。

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#include <iostream>
    #include <algorithm>
    using namespace std;
    int a[101];

    bool cmp(int x,int y)
    {
        return x>y;
    }

    int main()
    {
        int n;
        while(cin>>n){
            for(int i=0;i<n;i++){
                cin>>a[i];
            }
            sort(a,a+n,cmp);
            int sum1=0,sum2=0;
            for(int i=0;i<n;i++){
                if(i%2==0) sum1+=a[i];
                else sum2+=a[i];
            }
            cout<<sum1-sum2<<endl;
        }
        return 0;
    }

C

推式子。

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// LUOGU_RID: 174585431
#include<iostream>
using namespace std;
int c[4][4];
int main()
{
	for(int i=1;i<=3;i++)
	for(int j=1;j<=3;j++)
	cin>>c[i][j];
	if
	(
	c[1][3]==c[3][3]-c[3][1]+c[1][1]&&
	c[1][2]==c[2][2]-c[2][1]+c[1][1]&&
	c[2][3]==c[3][3]-c[3][1]+c[2][1]&&
	c[3][2]==c[3][1]-c[2][1]+c[2][2]
	)
	cout<<"Yes";
	else cout<<"No";
	return 0;
}

D

找最短路，其他无关的弄掉即可。

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#include <bits/stdc++.h>
#define MAX_N 55
using namespace std;
char mapp[MAX_N][MAX_N];
int n, m, cnt;
int dist[MAX_N][MAX_N];
struct node
{
    int x, y;
} q[MAX_N * MAX_N];
bool pd[MAX_N][MAX_N];
const int r[] = {1, -1, 0, 0}, w[] = {0, 0, 1, -1};
inline void BFS(int sx, int sy)
{
    int hd, tl, dx, dy, fx, fy;
    hd = tl = 1;
    q[1].x = sx;
    q[1].y = sy;
    while (hd <= tl)
    {
        fx = q[hd].x;
        fy = q[hd].y;
        hd++;
        for (int i = 0; i < 4; ++i)
        {
            dx = fx + r[i];
            dy = fy + w[i];
            if (dx < 1 || dy < 1 || dx > n || dy > m || mapp[dx][dy] == '#' || pd[dx][dy] == 1)
                continue;
            pd[dx][dy] = 1;
            tl++;
            q[tl].x = dx;
            q[tl].y = dy;
            dist[dx][dy] = dist[fx][fy] + 1;
            if (dx == n && dy == m)
                return;
        }
    }
}
int main()
{
    memset(dist, 127 / 3, sizeof dist);
    cin >> n >> m;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 1; j <= m; ++j)
        {
            cin >> mapp[i][j];
            if (mapp[i][j] == '#')
                cnt++;
        }
    }
    dist[1][1] = 1;
    pd[1][1] = 1;
    BFS(1, 1);
    int ans = n * m - cnt - dist[n][m];
    if (ans < 0)
        puts("-1");
    else
        cout << ans;
    return 0;
}