제출 #91044

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
91044		RezwanArefin01	Boat (APIO16_boat)	C++17	0 / 100	7 ms	2428 KiB

boat

///usr/bin/g++ -O2 $0 -o ${0%.cpp} && echo "----------" && ./${0%.cpp}; exit;
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii; 

const int N = 1024; 
const int mod = 1e9 + 7;

int n, a[N], b[N], len[N], dp[N][N]; 
int fact[N], inv[N];
map<int, int> com;

int Pow(int n, int p) {
    int ret = 1; while(p) {
        if(p & 1) ret = (ll) ret * n % mod; 
        n = (ll) n * n % mod; 
        p >>= 1; 
    } return ret; 
}

void precalc() {
    fact[0] = 1; 
    for(int i = 1; i < N; i++) 
        fact[i] = (ll) fact[i - 1] * i % mod; 
    inv[N - 1] = Pow(fact[N - 1], mod - 2);
    for(int i = N - 2; i >= 0; i--) 
        inv[i] = (ll) inv[i + 1] * (i + 1) % mod; 
}

int C(int n, int r) {
    int ret = (ll) fact[n] * inv[n - r] % mod;
    return (ll) ret * inv[r] % mod; 
}

void add(int &a, int b) {
    a += b; if(a >= mod) a -= mod; 
}

int main(int argc, char const *argv[]) {
    precalc(); 
    scanf("%d", &n);
    vector<int> v = {0}; 

    for(int i = 1; i <= n; i++) {
        scanf("%d %d", &a[i], &b[i]); b[i]++; 
        v.push_back(a[i]); 
        v.push_back(b[i]); 
    } 
    sort(v.begin(), v.end()); 
    v.erase(unique(v.begin(), v.end()), v.end()); 

    for(int i = 1; i < v.size(); i++) 
        com[v[i]] = i, len[i] = v[i] - v[i - 1]; 
    for(int i = 1; i <= n; i++)
        a[i] = com[a[i]], b[i] = com[b[i]]; 
    
    int m = v.size() - 1; 
    for(int i = 0; i <= m; i++) dp[0][i] = 1; 

    for(int i = 1; i <= n; i++) { dp[i][0] = 1; 
        for(int j = a[i]; j < b[i]; j++) {
            int cnt = 1; 
            dp[i][j] = (ll) len[j] * dp[i - 1][j - 1] % mod; 
            for(int k = i - 1; k >= 1; k--) 
                if(a[k] <= j && j < b[k]) 
                    add(dp[i][j], (ll) C(len[j], ++cnt) * dp[k - 1][j - 1] % mod); 
        }
        for(int j = 1; j <= m; j++) {
            add(dp[i][j], dp[i - 1][j]); 
            add(dp[i][j], dp[i][j -  1]); 
            add(dp[i][j], mod - dp[i - 1][j - 1]); 
        }        
    }
    add(dp[n][m], mod - 1); 
    printf("%d\n", dp[n][m]); 
}

컴파일 시 표준 에러 (stderr) 메시지

boat.cpp: In function 'int main(int, const char**)':
boat.cpp:54:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 1; i < v.size(); i++) 
                    ~~^~~~~~~~~~
boat.cpp:43:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
boat.cpp:47:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a[i], &b[i]); b[i]++; 
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42