Submission #1186588

#	Time	Username	Problem	Language	Result	Execution time	Memory
1186588		kl0989e	Necklace (Subtask 1-3) (BOI19_necklace1)	C++20	85 / 85	535 ms	106196 KiB

necklace

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define fi first
#define se second
#define pb push_back
#define vi vector<int>
#define vl vector<ll>
#define pi pair<int, int>
#define pl pair<ll,ll>
#define all(x) (x).begin(),(x).end()

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
	string a,b;
	cin >> a >> b;
	int n=a.size(),m=b.size();
	int ans=-1,aa=-1,bb=-1;
	for (int l=0; l<2; l++) {
		int dp[n+1][m+1];
		memset(dp,0,sizeof(dp));
		for (int i=n-1; i>=0; i--) {
			for (int j=m-1; j>=0; j--) {
				if (a[i]==b[j]) {
					dp[i][j]=dp[i+1][j+1]+1;
				}
			}
		}
		int dp2[n+1][m+1];
		memset(dp2,0,sizeof(dp2));
		for (int i=0; i<n; i++) {
			for (int j=0; j<m; j++) {
				dp2[i][j+dp[i][j]-1]=max(dp2[i][j+dp[i][j]-1],dp[i][j]);
			}
			for (int j=m-2; j>=0; j--) {
				dp2[i][j]=max(dp2[i][j],dp2[i][j+1]-1);
			} 
		}
		int dp3[n+1][m+1];
		memset(dp3,0,sizeof(dp2));
		for (int j=0; j<m; j++) {
			for (int i=0; i<n; i++) {
				dp3[i+dp[i][j]-1][j]=max(dp3[i+dp[i][j]-1][j],dp[i][j]);
			}
			for (int i=n-2; i>=0; i--) {
				dp2[i][j]=max(dp2[i][j],dp2[i][j+1]-1);
			} 
		}
		for (int i=0; i<n; i++) {
			for (int j=0; j<m; j++) {
				int t=(j>0?dp2[i][j-1]:0)+(i>0?dp3[i-1][j]:0);
				if (t>ans) {
					ans=t;
					aa=i-(i>0?dp3[i-1][j]:0);
					bb=j-(j>0?dp2[i][j-1]:0);
					if (l) {
						bb=j+(i>0?dp3[i-1][j]:0)-1;
						bb=m-1-bb;
					}
				}
			}
		}
		reverse(all(b));
	}
	cout << ans << '\n' << aa << ' ' << bb << '\n';
    return 0;
}

• Subtask 1: 25 / 25
• Subtask 2: 20 / 20
• Subtask 3: 40 / 40