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답안 #1005555

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1005555 2024-06-22T15:35:19 Z anango Necklace (Subtask 1-3) (BOI19_necklace1) C++17
9 / 85
 566 ms 600 KB 
#include <bits/stdc++.h>
#define int long long

using namespace std;
mt19937 rng;
int INF = 1LL<<60;
int p = 2071723;
int MOD = 1000000033;

string a;
string b;
int n,m;

vector<int> hashes;

void compute_hash(string s) {
    int n1 = s.size();
    hashes.clear();
    hashes=vector<int>(n1+1,0);
    int ha = 0;
    for (int i=0; i<n1; i++) {
        ha += s[i]-'a';
        ha *= p;
        ha %= MOD;
        hashes[i+1] = ha;
    }
    
}

int exp(int p, int n) {
    int ans=1;
    int r = p;
    for (int i=0; i<30; i++) {
        if (n&(1<<i)) {
            ans*=r;
            ans%=MOD;
        }
        r*=r;
        r%=MOD;
    }
    return ans;
}

int gethash(int l, int r) {
    int h1 = hashes[l];
    int h2 = hashes[r+1];
    h1 *= exp(p,r-l+1);
    h1%=MOD;
    int dif = h2-h1;
    dif%=MOD;
    dif+=MOD;
    dif%=MOD;
    return dif;
}

bool check(int a, int b, int length) {
    return gethash(a,a+length-1)==gethash(b,b+length-1);
}
bool verify(int i, int j, int length) {
    //checks if i...i+length-1 in a = j...j+length-1 in b
    return gethash(i,length-1)==gethash(n+j, length-1);
}

vector<pair<int,int>> solve() {
    compute_hash(a+b);
    int ans = 0;
    pair<int,int> xpos;
    pair<int,int> ypos;
    for (int trial=0; trial*ans<3000000; trial++) {
        int i,j;
        i=rng()%n;  
        j=rng()%m;
        if (a[i]!=b[j]) {
            continue;
        }
        int l,r;
        l=0;
        r=0;
        while (l+i>=0 && l+j>=0 && a[i+l]==b[j+l]) {
            //cout << "doing " << i <<" " << l <<" " << a[i+l] <<" " << b[j+l] << endl;
            l--;
        }
        l++;
        while (r+i<=n-1 && r+j<=m-1 && a[i+r]==b[j+r]) {
            r++;
        }
        r--;
        int length = r-l+1;
        int subans = length;
        if (subans>ans) {
            ans=subans;
            xpos={i+l,i+l+length};
            ypos={j+l,j+l+length};
        }
        for (int blubber=1; blubber<=length; blubber++) { //add it on both sides
            int la = i+r+1;
            int ra = i+r+blubber;
            int lb = j+l-blubber;
            int rb = j+l-1;
            if (!(0<=la && la<=n-1) || !(0<=lb && rb<=m-1)) {
                break;
            }
            if (gethash(la,ra)==gethash(n+lb,n+rb)) {
                int subans = blubber+length;
                if (subans>ans) {
                    //cout << a <<" " << b <<" " << ans <<" " << i <<" " << j <<" " << blubber <<" " << subans << endl;
                    //cout << la <<" " << ra <<" " << lb <<" " << rb << endl;
                    ans=subans;
                    xpos = {i+l,ra};
                    ypos = {lb,j+r};
                }
            }
        }

    }
    return {{ans,ans},xpos,ypos};

    
}

signed main() {
    //freopen("input.txt","r", stdin);
    //freopen("output.txt","w",stdout);
    cin >> a;
    cin >> b;
    n=a.size();
    m=b.size();
    vector<pair<int,int>> ans2;
    vector<int> ans(3);
    ans2=solve();
    ans[0] = ans2[0].first;
    ans[1] = ans2[1].first;
    ans[2] = ans2[2].first;
    reverse(b.begin(), b.end());
    ans2 = solve();
    if (ans2[0].first>ans[0]) {
        ans[0] = ans2[0].first;
        ans[1] = ans2[1].first;
        ans[2] = m-ans2[2].second-1;
    }
    reverse(a.begin(), a.end());
    ans2 = solve();
    if (ans2[0].first>ans[0]) {
        ans[0] = ans2[0].first;
        ans[1] = n-ans2[1].second-1;
        ans[2] = m-ans2[2].second-1;
    }
    /*reverse(b.begin(), b.end());
    ans2 = solve();
    if (ans2[0].first>ans[0]) {
        ans[0] = ans2[0].first;
        ans[1] = n-ans2[1].second-1;
        ans[2] = ans2[2].first;
    }*/
    cout << ans[0] << endl;
    cout << ans[1] <<" " << ans[2] << endl;


    //want to store for each x and j, the smallest t such that match[x][t]+t = j
    

}

Subtask #1
5.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 241 ms 348 KB Output is correct
2 Partially correct 123 ms 344 KB Output is partially correct
3 Correct 460 ms 436 KB Output is correct
4 Correct 229 ms 416 KB Output is correct
5 Correct 45 ms 344 KB Output is correct

Subtask #2
4.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 241 ms 348 KB Output is correct
2 Partially correct 123 ms 344 KB Output is partially correct
3 Correct 460 ms 436 KB Output is correct
4 Correct 229 ms 416 KB Output is correct
5 Correct 45 ms 344 KB Output is correct
6 Partially correct 227 ms 432 KB Output is partially correct
7 Correct 110 ms 344 KB Output is correct
8 Partially correct 474 ms 424 KB Output is partially correct
9 Correct 204 ms 424 KB Output is correct
10 Correct 10 ms 348 KB Output is correct
11 Correct 11 ms 456 KB Output is correct
12 Correct 442 ms 420 KB Output is correct

Subtask #3
0.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 241 ms 348 KB Output is correct
2 Partially correct 123 ms 344 KB Output is partially correct
3 Correct 460 ms 436 KB Output is correct
4 Correct 229 ms 416 KB Output is correct
5 Correct 45 ms 344 KB Output is correct
6 Partially correct 227 ms 432 KB Output is partially correct
7 Correct 110 ms 344 KB Output is correct
8 Partially correct 474 ms 424 KB Output is partially correct
9 Correct 204 ms 424 KB Output is correct
10 Correct 10 ms 348 KB Output is correct
11 Correct 11 ms 456 KB Output is correct
12 Correct 442 ms 420 KB Output is correct
13 Partially correct 297 ms 600 KB Output is partially correct
14 Correct 139 ms 344 KB Output is correct
15 Partially correct 566 ms 600 KB Output is partially correct
16 Partially correct 280 ms 348 KB Output is partially correct
17 Incorrect 3 ms 344 KB Output isn't correct
18 Halted 0 ms 0 KB -