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Submission #52968

# Submission time Handle Problem Language Result Execution time Memory
52968 2018-06-27T11:47:35 Z evpipis Boat (APIO16_boat) C++11
27 / 100
 2000 ms 5240 KB 
#include <bits/stdc++.h>
using namespace std;

#define pb push_back
const int len = 505, mod = 1e9+7;
int n, m = 0;
int po[2*len], dp[2][2*len][len][2], bi[2*len][len], l[len], r[len];
vector<int> vec;

int add(int a, int b){
    return (a+b)%mod;
}

int mul(int a, int b){
    return (a*1LL*b)%mod;
}

int pw(int a, int b){
    if (b == 0) return 1;
    if (b%2 == 0) return pw(mul(a, a), b/2);
    return mul(a, pw(mul(a, a), b/2));
}

int main(){
    scanf("%d", &n);
    for (int i = 1; i <= n; i++){
        scanf("%d %d", &l[i], &r[i]);
        vec.pb(l[i]), vec.pb(r[i]);
    }

    sort(vec.begin(), vec.end());
    for (int i = 0; i < vec.size(); i++)
        if (vec[i] != po[m])
            po[++m] = vec[i];

    //for (int i = 0; i <= m; i++)
      //  printf("i = %d, poi = %d\n", i, po[i]);

    for (int i = 0; i <= m; i++){
        bi[i][0] = 1;
        int s = po[i]-po[i-1] - 1;
        for (int k = 1; k <= min(s, n); k++)
            bi[i][k] = mul(bi[i][k-1], mul(s-k+1, pw(k, mod-2)));
    }

    for (int i = 0; i <= n; i++)
        for (int j = 0; j <= m+1; j++)
            for (int k = 0; k <= i; k++)
                for (int t = 0; t < 2; t++){
                    if ((i == 0 || j == 0) && (k == 0)){
                        dp[i&1][j][k][t] = 1;
                        continue;
                    }

                    int ans = 0;
                    if (k == 0){
                        for (int x = 0; x <= i; x++){
                            ans = add(ans, mul(dp[i&1][j-1][x][0], bi[j-1][x]));
                            ans = add(ans, mul(dp[i&1][j-1][x][1], bi[j-1][x-1]));
                        }
                    }
                    else{
                        ans = add(ans, dp[(i-1)&1][j][k][t]);
                        if (t == 0 && l[i] <= po[j-1]+1 && po[j]-1 <= r[i])
                            ans = add(ans, dp[(i-1)&1][j][k-1][0]);
                        if (t == 1 && l[i] <= po[j] && po[j] <= r[i])
                            ans = add(ans, dp[(i-1)&1][j][k-1][0]);
                    }

                    dp[i&1][j][k][t] = ans;
                }

    printf("%d\n", add(dp[n&1][m+1][0][0], mod-1));
    return 0;
}

Compilation message

boat.cpp: In function 'int main()':
boat.cpp:32:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < vec.size(); i++)
                     ~~^~~~~~~~~~~~
boat.cpp:25:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
boat.cpp:27:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &l[i], &r[i]);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2050 ms 5240 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2050 ms 5240 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 90 ms 5240 KB Output is correct
2 Correct 97 ms 5240 KB Output is correct
3 Correct 107 ms 5240 KB Output is correct
4 Correct 112 ms 5240 KB Output is correct
5 Correct 87 ms 5240 KB Output is correct
6 Correct 96 ms 5240 KB Output is correct
7 Correct 92 ms 5240 KB Output is correct
8 Correct 90 ms 5240 KB Output is correct
9 Correct 97 ms 5240 KB Output is correct
10 Correct 91 ms 5240 KB Output is correct
11 Correct 86 ms 5240 KB Output is correct
12 Correct 88 ms 5240 KB Output is correct
13 Correct 87 ms 5240 KB Output is correct
14 Correct 118 ms 5240 KB Output is correct
15 Correct 121 ms 5240 KB Output is correct
16 Correct 38 ms 5240 KB Output is correct
17 Correct 39 ms 5240 KB Output is correct
18 Correct 39 ms 5240 KB Output is correct
19 Correct 41 ms 5240 KB Output is correct
20 Correct 45 ms 5240 KB Output is correct

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2050 ms 5240 KB Time limit exceeded
2 Halted 0 ms 0 KB -