蓝桥杯真题讲解:更小的数(区间DP)
蓝桥杯真题讲解:更小的数(区间DP)
- 一、视频讲解
- 二、正解代码
一、视频讲解
蓝桥杯真题讲解:更小的数(区间DP)
二、正解代码
#include<bits/stdc++.h>
#define endl '\n'
#define deb(x) cout << #x << " = " << x << '\n';
#define INF 0x3f3f3f3f
using namespace std;
const int N = 5e3 + 10;
int f[N][N];void solve()
{string s;cin >> s;int ans = 0;for(int len = 2; len <= s.size(); len ++){for(int l = 0; l + len - 1 < s.size(); l ++){int r = l + len - 1;if(s[l] > s[r])f[l][r] = 1;else if(s[l] == s[r])f[l][r] = f[l + 1][r - 1]; ans += f[l][r];}}cout << ans << endl;
}
signed main()
{ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);int t;t = 1;//cin >> t;while(t--)solve();
}