Submission #737051

#	Time	Username	Problem	Language	Result	Execution time	Memory
737051		minhcool	Catfish Farm (IOI22_fish)	C++17	70 / 100	282 ms	296708 KiB

fish

#include<bits/stdc++.h>
using namespace std;
 
#define ll long long
//#define int long long
#define fi first
#define se second
#define pb push_back
//#define mp make_pair
 
typedef pair<int, int> ii;
typedef pair<ii, int> iii;
typedef pair<ii, ii> iiii;
 
const int N = 3e5 + 5;
 
const int oo = 1e18 + 7, mod = 1e9 + 7;
 
int n, m;
 
long long val[3005][3005], pref[3005][3005];
 
// dp[row_i][row_j][i - 1 > or = or <]
long long dp[3005][3005][2];
 
ll x[N], y[N], w[N];
 
ll solve1(){
	ll tol = 0;
	for(int i = 1; i <= m; i++) tol += w[i];
	return tol;
}
 
map<ii, ll> mp;
 
ll solve2(){
	for(int i = 1; i <= m; i++) mp[{x[i], y[i]}] = w[i];
	if(n >= 3){
		ll mx = -1, total = 0;
		for(int i = 1; i <= n; i++) total += mp[{2, i}];
		mx = total;
		for(int i = 1; i <= n; i++){
			total += (mp[{1, i}] - mp[{2, i}]);
			mx = max(mx, total);
		}
		return mx;
	}
	else{
		return max(mp[{1, 1}] + mp[{1, 2}], mp[{2, 1}] + mp[{2, 2}]);
	}
}
 
ll dp1[N][2][2];
 
ll solve3(){
	//cout << "OK\n";
	for(int i = 1; i <= m; i++) mp[{x[i], y[i]}] = w[i];
	for(int i = 1; i <= n; i++){
		for(int j = 0; j < 2; j++){
			for(int k = 0; k < 2; k++) dp1[i][j][k] = -oo;
		}
	}
	dp1[1][0][0] = dp1[1][1][0] = 0;
	for(int i = 2; i <= (n + 1); i++){
		for(int j = 0; j < 2; j++){
			if(i == (n + 1) && j) break;
			for(int k = 0; k < 2; k++){
				for(int h = 0; h < 2; h++){
					dp1[i][j][k] = max(dp1[i][j][k], dp1[i - 1][k][h] + mp[{i - 1, 1}] * (!k && (j | h)));
				}
				//cout << i << " " << j << " " << k << " " << dp1[i][j][k] << "\n";
			}
		}
	}
	return max(dp1[n + 1][0][0], dp1[n + 1][0][1]);
}
 
 
long long max_weights(int _n, int _m, vector<int> _x, vector<int> _y, vector<int> _w){
	n = _n, m = _m;
	bool chk1 = 1, chk2 = 1, chk3 = 1;
	for(int i = 0; i < m; i++){
		x[i + 1] = _x[i] + 1, y[i + 1] = _y[i] + 1, w[i + 1] = _w[i];
		chk1 &= (!(_x[i] & 1));
		chk2 &= (_x[i] <= 1);
		chk3 &= (_y[i] <= 0);
		if(n <= 3000) val[_x[i] + 1][_y[i] + 1] += (long long)_w[i];
	}
	if(n <= 3000){
		for(int i = 1; i <= n; i++){
			for(int j = 1; j <= n; j++) pref[i][j] = pref[i][j - 1] + val[i][j];
		}
		for(int i = 0; i <= n; i++){
			for(int j = 0; j <= n; j++){
				dp[i][j][0] = dp[i][j][1] = -oo;
			}
		}
		//dp[0][0][0] = 0;
		//15206896898496
		for(int i = 0; i <= n; i++){
			//dp[2][i][0] = pref[1][i];// 0 -> <=
			//dp[2][i][1] = pref[2][i;
			dp[1][i][0] = 0;
		}
		for(int i = 2; i <= n + 1; i++){
			// calculate (i - 1)
			long long maximum = -oo;
			for(int nxt = 0; nxt <= n; nxt++){
				maximum = max(maximum, dp[i - 1][nxt][0] - pref[i - 1][nxt]);
				dp[i][nxt][0] = max(dp[i][nxt][0], maximum + pref[i - 1][nxt]);
			}
			maximum = -oo;
			for(int nxt = n; nxt >= 0; nxt--){
				dp[i][nxt][1] = max(dp[i][nxt][1], maximum - pref[i][nxt]);
				maximum = max(maximum, dp[i - 1][nxt][1] + pref[i][nxt]);
			}
			for(int lst = 0; lst <= n; lst++){
				// 0 - 0
				/*
				for(int nxt = lst; nxt <= n; nxt++){
					dp[i][nxt][0] = max(dp[i][nxt][0], dp[i - 1][lst][0] + (pref[i - 1][nxt] - pref[i - 1][lst]));
				}
				// 1 - 1
				for(int nxt = lst - 1; nxt >= 0; nxt--){
					dp[i][nxt][1] = max(dp[i][nxt][1], dp[i - 1][lst][1] + pref[i][lst] - pref[i][nxt]);	
				}*/
				// 0 - 1
				if(lst == n){
					for(int nxt = 0; nxt < n; nxt++) dp[i][nxt][1] = max(dp[i][nxt][1], dp[i - 1][n][0] + pref[i][n] - pref[i][nxt]);
				}
				// 1 - 0
				if(!lst){
					dp[i][0][0] = max(dp[i][0][0], dp[i - 1][0][1]);
					for(int nxt = 1; nxt <= n; nxt++) dp[i][nxt][0] = max(dp[i][nxt][0], max(dp[i - 1][0][0] + pref[i - 1][nxt], dp[i - 1][0][1]));
				}
			}
		}
		return max(dp[n + 1][0][0], dp[n + 1][0][1]);
	}
	else if(chk1) return solve1();
	else if(chk2) return solve2();
	else if(chk3) return solve3();
}
 
/*
void process(){
	int n, m;
	vector<int> a, b, c;
	cin >> n >> m;
	for(int i = 1; i <= m; i++){
		int x, y, z;
		cin >> x >> y >> z;
		a.pb(x), b.pb(y), c.pb(z);
	}
	cout << max_weights(n, m, a, b, c) << "\n";
}
 
signed main(){
	ios_base::sync_with_stdio(0);
	freopen("fish.inp", "r", stdin);
	//freopen("fish.out", "w", stdout);
	//cout << "OK\n";
	//return 0;
	process();
}
*/

Compilation message (stderr)

fish.cpp:17:21: warning: overflow in conversion from 'double' to 'int' changes value from '1.0e+18' to '2147483647' [-Woverflow]
   17 | const int oo = 1e18 + 7, mod = 1e9 + 7;
      |                ~~~~~^~~
fish.cpp: In function 'long long int max_weights(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:143:1: warning: control reaches end of non-void function [-Wreturn-type]
  143 | }
      | ^

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 9 / 9
• Subtask 4: 14 / 14
• Subtask 5: 21 / 21
• Subtask 6: 17 / 17
• Subtask 7: 0 / 14
• Subtask 8: 0 / 16