Codeforces Round #703 (Div. 2) （自閉場）

A. Shifting Stacks

這題我能記很久，直接給我打自閉了，從開賽一直到了最后，我就一個菜雞
題意非常簡單，給你n個數，讓你把他們構造成遞增的，然后只能從后往前，你直接想就行了，直接構造0 1 2 3 4 5 6 7 8 9…n如果可以的話，就是yes，不可以的話就是no

然后上我第一遍的代碼

#include <bits/stdc++.h>
#define int long long
#define BUFF ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
using namespace std;
const int N = 2e5 + 10;
const int INF = 0x3f3f3f3f;
inline int read()
{
    int x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x * f;
}
int a[N];
signed main()
{
    /*  
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
*/
    int T;
    T = read();
    while (T--)
    {
        int n;
        n = read();
        bool flag = true;
        int cnt = 0;
        for (int i = 1; i <= n; i++)
        {
            a[i] = read();
        }
        for (int i = 1; i < n; i++)
        {
            int ans = a[i] - cnt;
            a[i] = cnt;
            cnt++;
            if (ans < 0)
            {
                flag = false;
                break;
            }
            a[i + 1] += ans;
            if (a[i] >= a[i + 1])
            {
                flag = false;
                break;
            }
        }
        if (a[n] <= a[n - 1])
        {
            flag = false;
        }
        if (flag)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}

這個讓人直接wa掉，因為我少了一個特判，如果n==1的時候，我要直接yes，而不是判斷a[1]和a[0]的關系

然后下面是ac的代碼

#include <bits/stdc++.h>
#define int long long
#define BUFF ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
using namespace std;
const int N = 2e5 + 10;
const int INF = 0x3f3f3f3f;
inline int read()
{
    int x = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x * f;
}
int a[N];
signed main()
{
    /*  
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
*/
    int T;
    T = read();
    while (T--)
    {
        int n;
        n = read();

        bool flag = true;
        int cnt = 0;
        for (int i = 1; i <= n; i++)
        {
            a[i] = read();
        }
        if (n == 1)
        {
            cout << "YES" << endl;
            continue;
        }
        for (int i = 1; i < n; i++)
        {
            int ans = a[i] - cnt;
            a[i] = cnt;
            cnt++;
            if (ans < 0)
            {
                flag = false;
                break;
            }
            a[i + 1] += ans;
            if (a[i] >= a[i + 1])
            {
                flag = false;
                break;
            }
        }
        if (a[n] <= a[n - 1])
        {
            flag = false;
        }
        if (flag)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}

就加了一個特判就好了，我直接上圖，我wa的人傻了的圖

剩下的題補完再更新