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Submission #255347

# Submission time Handle Problem Language Result Execution time Memory
255347 2020-07-31T18:09:45 Z DavidDamian Mecho (IOI09_mecho) C++11
100 / 100
 223 ms 11388 KB 
#include <bits/stdc++.h>
using namespace std;
///Binary Search
///BFS
///Determine the number of minutes that Mecho can stay eating honey (moment he leaves -1)
///Use two BFS, for the bees and for Mecho, second has parameter "fuel" since he can travel more than 1 step per minute
struct node
{
    int i,j;
    node(){}
    node(int i,int j) : i(i),j(j){}
};
int n,s;
char board[805][805];
int bee[805][805];
int d[805][805];
int color[805][805];
int fuel[805][805];
int dx[4]={1,-1,0,0};
int dy[4]={0,0,1,-1};
queue<node> Q;
node start,finish;
void bfsBee()
{
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            bee[i][j]=INT_MAX;
            if(board[i][j]=='H'){
                Q.push(node(i,j));
                bee[i][j]=0;
                color[i][j]=-1;
            }
        }
    }
    while(Q.size()){
        node u=Q.front();Q.pop();
        for(int mov=0;mov<4;mov++){
            int i=u.i+dx[mov];
            int j=u.j+dy[mov];
            if(i<1 || i>n) continue;
            if(j<1 || j>n) continue;
            if(board[i][j]=='T' || board[i][j]=='D') continue;
            if(color[i][j]==0){
                color[i][j]=-1;
                Q.push(node(i,j));
                bee[i][j]=bee[u.i][u.j]+1;
            }
        }
    }
}
void bfsMecho(int init_d)
{
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            d[i][j]=INT_MAX;
            color[i][j]=0;
        }
    }
    if(bee[start.i][start.j]<=init_d-1) return;
    d[start.i][start.j]=init_d-1;
    fuel[start.i][start.j]=0;
    color[start.i][start.j]=init_d;
    Q.push(start);
    while(Q.size()){
        node u=Q.front();Q.pop();
        if(d[u.i][u.j]==bee[u.i][u.j] && fuel[u.i][u.j]==0) continue; //Bees caught Mecho
        for(int mov=0;mov<4;mov++){
            int i=u.i+dx[mov];
            int j=u.j+dy[mov];
            if(i<1 || i>n) continue;
            if(j<1 || j>n) continue;
            if(board[i][j]=='T') continue;
            if(color[i][j]!=init_d){
                d[i][j]=(fuel[u.i][u.j]>0)? d[u.i][u.j] : d[u.i][u.j]+1;
                if(bee[i][j]<d[i][j]) continue; //Already filled with bees
                fuel[i][j]=(fuel[u.i][u.j]>0)? fuel[u.i][u.j]-1 : s-1;
                color[i][j]=init_d;
                Q.push(node(i,j));
            }
        }
    }
}
bool valid(int k)
{
    bfsMecho(k);
    return d[finish.i][finish.j]!=INT_MAX;
}
int binarySearch()
{
    int k=0;
    for(int b=10000;b>=1;b/=2){
        while(valid(k+b)) k+=b;
    }
    return k-1;
}
int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin>>n>>s;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cin>>board[i][j];
            if(board[i][j]=='M') start={i,j};
            if(board[i][j]=='D') finish={i,j};
        }
    }
    bfsBee();
    int maximum=binarySearch();
    cout<<maximum<<'\n';
    return 0;
}

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 0 ms 384 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 0 ms 512 KB Output is correct
6 Correct 0 ms 512 KB Output is correct
7 Correct 148 ms 10232 KB Output is correct
8 Correct 1 ms 512 KB Output is correct
9 Correct 1 ms 512 KB Output is correct
10 Correct 1 ms 512 KB Output is correct
11 Correct 1 ms 512 KB Output is correct
12 Correct 1 ms 1152 KB Output is correct
13 Correct 1 ms 896 KB Output is correct
14 Correct 1 ms 1024 KB Output is correct
15 Correct 0 ms 640 KB Output is correct
16 Correct 1 ms 512 KB Output is correct
17 Correct 1 ms 640 KB Output is correct
18 Correct 1 ms 640 KB Output is correct
19 Correct 1 ms 640 KB Output is correct
20 Correct 1 ms 640 KB Output is correct
21 Correct 1 ms 768 KB Output is correct
22 Correct 1 ms 768 KB Output is correct
23 Correct 1 ms 896 KB Output is correct
24 Correct 1 ms 896 KB Output is correct
25 Correct 1 ms 1024 KB Output is correct
26 Correct 1 ms 1024 KB Output is correct
27 Correct 1 ms 1024 KB Output is correct
28 Correct 1 ms 1152 KB Output is correct
29 Correct 1 ms 1152 KB Output is correct
30 Correct 1 ms 1152 KB Output is correct
31 Correct 1 ms 1152 KB Output is correct
32 Correct 1 ms 1152 KB Output is correct
33 Correct 10 ms 4352 KB Output is correct
34 Correct 11 ms 4736 KB Output is correct
35 Correct 28 ms 5024 KB Output is correct
36 Correct 15 ms 5120 KB Output is correct
37 Correct 13 ms 5376 KB Output is correct
38 Correct 39 ms 5760 KB Output is correct
39 Correct 19 ms 5760 KB Output is correct
40 Correct 18 ms 6144 KB Output is correct
41 Correct 49 ms 6400 KB Output is correct
42 Correct 26 ms 6264 KB Output is correct
43 Correct 22 ms 6784 KB Output is correct
44 Correct 60 ms 7040 KB Output is correct
45 Correct 35 ms 6784 KB Output is correct
46 Correct 29 ms 7424 KB Output is correct
47 Correct 72 ms 7680 KB Output is correct
48 Correct 43 ms 7424 KB Output is correct
49 Correct 36 ms 8192 KB Output is correct
50 Correct 91 ms 8440 KB Output is correct
51 Correct 56 ms 8064 KB Output is correct
52 Correct 51 ms 8952 KB Output is correct
53 Correct 118 ms 9208 KB Output is correct
54 Correct 71 ms 8576 KB Output is correct
55 Correct 58 ms 9592 KB Output is correct
56 Correct 145 ms 9728 KB Output is correct
57 Correct 100 ms 9336 KB Output is correct
58 Correct 84 ms 10240 KB Output is correct
59 Correct 171 ms 10444 KB Output is correct
60 Correct 115 ms 9848 KB Output is correct
61 Correct 91 ms 10872 KB Output is correct
62 Correct 198 ms 11128 KB Output is correct
63 Correct 141 ms 11000 KB Output is correct
64 Correct 223 ms 11156 KB Output is correct
65 Correct 210 ms 11000 KB Output is correct
66 Correct 196 ms 11000 KB Output is correct
67 Correct 151 ms 11076 KB Output is correct
68 Correct 73 ms 11128 KB Output is correct
69 Correct 61 ms 11160 KB Output is correct
70 Correct 59 ms 11128 KB Output is correct
71 Correct 54 ms 11128 KB Output is correct
72 Correct 48 ms 9208 KB Output is correct
73 Correct 54 ms 11388 KB Output is correct
74 Correct 83 ms 11384 KB Output is correct
75 Correct 98 ms 11384 KB Output is correct
76 Correct 96 ms 11384 KB Output is correct
77 Correct 88 ms 11384 KB Output is correct
78 Correct 96 ms 10024 KB Output is correct
79 Correct 69 ms 9592 KB Output is correct
80 Correct 90 ms 9800 KB Output is correct
81 Correct 120 ms 9848 KB Output is correct
82 Correct 89 ms 9848 KB Output is correct
83 Correct 114 ms 9976 KB Output is correct
84 Correct 110 ms 9848 KB Output is correct
85 Correct 121 ms 9976 KB Output is correct
86 Correct 116 ms 9976 KB Output is correct
87 Correct 131 ms 10104 KB Output is correct
88 Correct 111 ms 10232 KB Output is correct
89 Correct 127 ms 9976 KB Output is correct
90 Correct 163 ms 10104 KB Output is correct
91 Correct 144 ms 10104 KB Output is correct
92 Correct 139 ms 10104 KB Output is correct