Submission #1102871

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102871		salmon	Mecho (IOI09_mecho)	C++14	100 / 100	371 ms	3068 KiB

mecho

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

int N;
int S;
vector<pair<int,int>> trans = {{1,0}, {-1,0},{0,1},{0,-1}};
char clst[810][810];
int s1,s2;
int f1,f2;
queue<pair<int,int>> q[2];
queue<pair<int,int>> m[2];
vector<pair<int,int>> spood;
bool visited[810][810];
bool vt[810][810];
int cq,cm;

bool check(int i, int j){
    if(i < 0) return false;
    if(i >= N) return false;
    if(j < 0) return false;
    if(j >= N) return false;
    return true;
}

void spreadhoney(int it){
    while(!q[it].empty()){
        pair<int,int> ii = q[it].front();
        q[it].pop();

        int i = ii.first;
        int j = ii.second;

        if(visited[i][j]) continue;
        visited[i][j] = true;
        vt[i][j] = true;

        for(pair<int,int> ii : trans){
            int ni = ii.first + i;
            int nj = ii.second + j;

            if(!check(ni,nj)) continue;
            if(visited[ni][nj]) continue;
            q[1 - it].push({ni,nj});
        }
    }
}

int main(){
    scanf(" %d",&N);
    scanf(" %d",&S);

    for(int i = 0; i < N; i++){
        for(int j = 0; j < N; j++){
            scanf(" %c",&clst[i][j]);
        }
    }

    for(int i = 0; i < N; i++){
        for(int j = 0; j < N; j++){
            visited[i][j] = false;
            vt[i][j] = false;
        }
    }

    for(int i = 0; i < N; i++){
        for(int j = 0; j < N; j++){
            if(clst[i][j] == 'T'){
                visited[i][j] = true;
                vt[i][j] = true;
            }
            else if(clst[i][j] == 'H'){
                q[1].push({i,j});
            }
            else if(clst[i][j] == 'M'){
                s1 = i;
                s2 = j;
            }
            else if(clst[i][j] == 'D'){
                f1 = i;
                f2 = j;
                visited[i][j] = true;
            }
        }
    }

    cq = 0;
    cm = 0;

    spreadhoney(1);

    vt[s1][s2] = true;

    for(pair<int,int> ii : trans){
        int ni = s1 + ii.first;
        int nj = s2 + ii.second;

        if(!check(ni,nj)) continue;
        m[0].push({ni,nj});
    }

    bool flag;

    while(true){
        int it = cm % 2;

        bool done = false;

        for(int i = 0; i < S - 1; i++, cm++){
            it = cm % 2;

            while(!m[it].empty()){
                pair<int,int> ii = m[it].front();
                m[it].pop();

                int i = ii.first;
                int j = ii.second;

                if(i == f1 && j == f2){
                    done = true;
                    flag = true;
                    break;
                }
                if(vt[i][j]) continue;
                vt[i][j] = true;

                for(pair<int,int> ii : trans){
                    int ni = i + ii.first;
                    int nj = j + ii.second;

                    if(!check(ni,nj)) continue;
                    if(vt[ni][nj]) continue;
                    m[1 - it].push({ni,nj});
                }
            }

            if(done) break;

            if(m[1 - it].empty()){
                done = true;
                flag = false;
                break;
            }
        }

        if(done) break;

        it = cq % 2;
        spreadhoney(it);
        cq++;

        it = cm % 2;

        while(!m[it].empty()){
            pair<int,int> ii = m[it].front();
            m[it].pop();

            int i = ii.first;
            int j = ii.second;
            //printf("%d %d\n",i,j);

            if(i == f1 && j == f2){
                done = true;
                flag = true;
                break;
            }
            if(vt[i][j]) continue;
            vt[i][j] = true;

            for(pair<int,int> ii : trans){
                int ni = i + ii.first;
                int nj = j + ii.second;

                if(!check(ni,nj)) continue;
                m[1 - it].push({ni,nj});
            }
        }
        //printf("\n");

        if(done) break;

        if(m[1 - it].empty()){
            done = true;
            flag = false;
            break;
        }

        cm++;

        if(done) break;
    }

    if(!flag){
        printf("-1");
        return 0;
    }

    int s = 0;
    int e = 800*800;
    int m1;

    while(s != e){
        m1 = (s + e + 1)/2;

        for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                visited[i][j] = false;
                vt[i][j] = false;
            }
        }

        while(!m[0].empty()) m[0].pop();
        while(!m[1].empty()) m[1].pop();
        while(!q[0].empty()) q[0].pop();
        while(!q[1].empty()) q[1].pop();

        for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                if(clst[i][j] == 'T'){
                    visited[i][j] = true;
                    vt[i][j] = true;
                }
                else if(clst[i][j] == 'H'){
                    q[1].push({i,j});
                }
                else if(clst[i][j] == 'D'){
                    visited[i][j] = true;
                }
            }
        }

        cq = 0;
        cm = 0;

        spreadhoney(1);

        vt[s1][s2] = true;

        for(pair<int,int> ii : trans){
            int ni = s1 + ii.first;
            int nj = s2 + ii.second;

            if(!check(ni,nj)) continue;
            m[0].push({ni,nj});
        }

        for(int i = 0; i < m1; i++, cq++){
            int it = cq % 2;

            spreadhoney(it);
        }

        if(visited[s1][s2]){
            e = m1 - 1;
            continue;
        }

        /*for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                printf("%d ",visited[i][j]);
            }
            printf("\n");
        }
        printf("\n");*/

        bool flag;

        while(true){
            int it = cm % 2;

            bool done = false;

            for(int i = 0; i < S - 1; i++, cm++){
                it = cm % 2;

                while(!m[it].empty()){
                    pair<int,int> ii = m[it].front();
                    m[it].pop();

                    int i = ii.first;
                    int j = ii.second;
                    //printf("%d %d\n",i,j);

                    if(i == f1 && j == f2){
                        done = true;
                        flag = true;
                        break;
                    }
                    if(vt[i][j]) continue;
                    vt[i][j] = true;

                    for(pair<int,int> ii : trans){
                        int ni = i + ii.first;
                        int nj = j + ii.second;

                        if(!check(ni,nj)) continue;
                        m[1 - it].push({ni,nj});
                    }
                }
                //printf("\n");

                if(done) break;

                if(m[1 - it].empty()){
                    done = true;
                    flag = false;
                    break;
                }
            }

            if(done) break;

            it = cq % 2;
            spreadhoney(it);
            cq++;

            it = cm % 2;

            while(!m[it].empty()){
                pair<int,int> ii = m[it].front();
                m[it].pop();

                int i = ii.first;
                int j = ii.second;
                //printf("%d %d\n",i,j);

                if(i == f1 && j == f2){
                    done = true;
                    flag = true;
                    break;
                }
                if(vt[i][j]) continue;
                vt[i][j] = true;

                for(pair<int,int> ii : trans){
                    int ni = i + ii.first;
                    int nj = j + ii.second;

                    if(!check(ni,nj)) continue;
                    m[1 - it].push({ni,nj});
                }
            }
            //printf("\n");

            if(done) break;

            if(m[1 - it].empty()){
                done = true;
                flag = false;
                break;
            }

            cm++;

            if(done) break;
        }

        if(flag){
            s = m1;
        }
        else{
            e = m1 - 1;
        }
    }

    printf("%d",s);
}
/*
7 3
TTTTTTT
TGGGGGT
THGGGGG
MGGGGGD
TGGTTTT
TGGGGGT
TTTTTHT
*/

Compilation message (stderr)

mecho.cpp: In function 'int main()':
mecho.cpp:49:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |     scanf(" %d",&N);
      |     ~~~~~^~~~~~~~~~
mecho.cpp:50:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |     scanf(" %d",&S);
      |     ~~~~~^~~~~~~~~~
mecho.cpp:54:18: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |             scanf(" %c",&clst[i][j]);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100