Submission #838093

#	Time	Username	Problem	Language	Result	Execution time	Memory
838093		jasmin	Mutating DNA (IOI21_dna)	C++17	100 / 100	36 ms	9736 KiB

dna

//IOI 2021
#include<bits/stdc++.h>
using namespace std;

const int N=1e5+5;
int cnta[N][3];
int cntb[N][3];

int ps[N][3][3];

void init(string a, string b){
    int n=a.size();
    vector<int> enc = {'A', 'C', 'T'};
    map<char, int> dec;
    dec['A']=0;
    dec['C']=1;
    dec['T']=2;

    for(int i=0; i<n; i++){
        
        for(int j=0; j<3; j++){

            cnta[i+1][j] = cnta[i][j];
            cntb[i+1][j] = cntb[i][j];

            if(a[i] == enc[j]){
                cnta[i+1][j]++;
            }
            if(b[i] == enc[j]){
                cntb[i+1][j]++;
            }
        }
    }

    for(int i=0; i<n; i++){

        for(int j=0; j<3; j++){
            for(int k=0; k<3; k++){
                ps[i+1][j][k] = ps[i][j][k];
            }
        }

        int j = dec[a[i]];
        int k = dec[b[i]];

        if(j==k) continue;

        ps[i+1][j][k]++;
    }
}

int get_distance(int x, int y){

    for(int j=0; j<3; j++){

        if(cnta[y+1][j]-cnta[x][j] != cntb[y+1][j]-cntb[x][j]){
            return -1;
        }
    }

    int ans1=0;
    int ans2=0;
    for(int j=0; j<3; j++){
        for(int k=0; k<j; k++){

            int a=ps[y+1][j][k] - ps[x][j][k];
            int b=ps[y+1][k][j] - ps[x][k][j];

            ans1 += min(a, b);
            ans2 += max(a, b)-min(a, b);
        }
    }

    assert(ans2%3 == 0);
    int ans = ans1 + 2*ans2/3;
    return ans;
}

• Subtask 1: 21 / 21
• Subtask 2: 22 / 22
• Subtask 3: 13 / 13
• Subtask 4: 28 / 28
• Subtask 5: 16 / 16