Submission #555112

#	Time	Username	Problem	Language	Result	Execution time	Memory
555112		kwongweng	Boat (APIO16_boat)	C++17	31 / 100	2107 ms	490128 KiB

boat

/*
Solution for APIO 2016 - Boat
Tags : 
*/

#include <bits/stdc++.h>
using namespace std;
 
#pragma GCC target ("avx2")
#pragma GCC optimization ("Ofast")
#pragma GCC optimization ("unroll-loops")
 
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef long double ld;
typedef pair<ll, ll> pll;
#define FOR(i, a, b) for(int i = a; i < b; i++)
#define ROF(i, a, b) for(int i = a; i >= b; i--)
#define ms memset
#define pb push_back
#define fi first
#define se second
 
ll MOD = 1000000007;
 
ll power(ll base, ll n){
	if (n == 0) return 1;
	if (n == 1) return base;
	ll halfn = power(base, n/2);
	if (n % 2 == 0) return (halfn * halfn) % MOD;
	return (((halfn * halfn) % MOD) * base) % MOD;
}
 
ll inverse(ll n){
	return power(n, MOD-2);
}
 
ll add(ll a, ll b){
	return (a+b) % MOD;
}
 
ll mul(ll a, ll b){
	a %= MOD;
	return (a*b) % MOD;
}
 
ll gcd(ll a, ll b){
    if (a == 1) return 1;
    if (a == 0) return b;
    return gcd(b%a, a);
}

void solve(){
    int n; cin >> n;
    vector<ll> a(n), b(n); FOR(i,0,n) cin >> a[i] >> b[i];
    vector<ll> dp[n];
    vector<ll> pre[n];
    map<ll, ll> mp;
    ll ans = 0;
    
    FOR(i,0,n){
        dp[i].pb(1);
        FOR(j,0,i){
            if (a[i] < a[j]) continue;
            dp[i][0] += pre[j][min(b[j]-a[j]+1, a[i]-a[j])];
            dp[i][0] %= MOD;
        }
        FOR(j,0,b[i]-a[i]+1){
            ll val = (dp[i][j] + mp[j+a[i]]) % MOD;
            dp[i].pb(val);
        }
        pre[i].pb(0);
        FOR(j,0,b[i]-a[i]+1){
            ll val = (pre[i][j] + dp[i][j]) % MOD;
            pre[i].pb(val);
            ll val2 = (mp[j+a[i]] + dp[i][j]) % MOD;
            mp[j+a[i]] = val2;
        }
        ans = (ans + pre[i][b[i]-a[i]+1]) % MOD;
    }
    
    cout << ans;
}
 
int main() {
    ios::sync_with_stdio(false);
    if (fopen("input.txt", "r")) {
		freopen("input.txt", "r", stdin);
		freopen("output.txt", "w", stdout);
	}
    int TC = 1;
    //cin >> TC;
    FOR(i, 1, TC+1){
        //cout << "Case #" << i << ": ";
        solve();
    }
}

Compilation message (stderr)

boat.cpp:10: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   10 | #pragma GCC optimization ("Ofast")
      | 
boat.cpp:11: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   11 | #pragma GCC optimization ("unroll-loops")
      | 
boat.cpp: In function 'int main()':
boat.cpp:90:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |   freopen("input.txt", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
boat.cpp:91:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |   freopen("output.txt", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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