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답안 #1005564

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
1005564 2024-06-22T15:41:24 Z anango Necklace (Subtask 1-3) (BOI19_necklace1) C++17
17 / 85
 1309 ms 736 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<12000000; 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};
        }
        if (subans<=ans/2) {
            continue;
        }
        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 533 ms 344 KB Output is correct
2 Partially correct 299 ms 348 KB Output is partially correct
3 Correct 770 ms 416 KB Output is correct
4 Correct 429 ms 348 KB Output is correct
5 Partially correct 67 ms 348 KB Output is partially correct

Subtask #2
4.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 533 ms 344 KB Output is correct
2 Partially correct 299 ms 348 KB Output is partially correct
3 Correct 770 ms 416 KB Output is correct
4 Correct 429 ms 348 KB Output is correct
5 Partially correct 67 ms 348 KB Output is partially correct
6 Partially correct 545 ms 344 KB Output is partially correct
7 Correct 303 ms 420 KB Output is correct
8 Partially correct 474 ms 416 KB Output is partially correct
9 Correct 310 ms 428 KB Output is correct
10 Correct 13 ms 348 KB Output is correct
11 Correct 16 ms 448 KB Output is correct
12 Correct 1093 ms 592 KB Output is correct

Subtask #3
8.0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 533 ms 344 KB Output is correct
2 Partially correct 299 ms 348 KB Output is partially correct
3 Correct 770 ms 416 KB Output is correct
4 Correct 429 ms 348 KB Output is correct
5 Partially correct 67 ms 348 KB Output is partially correct
6 Partially correct 545 ms 344 KB Output is partially correct
7 Correct 303 ms 420 KB Output is correct
8 Partially correct 474 ms 416 KB Output is partially correct
9 Correct 310 ms 428 KB Output is correct
10 Correct 13 ms 348 KB Output is correct
11 Correct 16 ms 448 KB Output is correct
12 Correct 1093 ms 592 KB Output is correct
13 Partially correct 621 ms 736 KB Output is partially correct
14 Correct 275 ms 348 KB Output is correct
15 Partially correct 654 ms 520 KB Output is partially correct
16 Partially correct 269 ms 344 KB Output is partially correct
17 Correct 3 ms 348 KB Output is correct
18 Correct 16 ms 504 KB Output is correct
19 Correct 261 ms 348 KB Output is correct
20 Correct 1309 ms 472 KB Output is correct
21 Partially correct 1302 ms 480 KB Output is partially correct