custom struct comparator and constructor usage/example

#include <iostream>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <unordered_map>
#include <numeric>
#include <iomanip>
using namespace std;
#define pii pair<long long, long long>
#define ll long long
#define FAST ios_base::sync_with_stdio(false); cin.tie(NULL)
#define mp(x1, x2) ( make_pair(x1, x2) )
const long long dx[4] = {1, 0, 0, -1}, dy[4] = {0, 1, -1, 0};
const long long dl[2] = {1, -1};
const long long MOD = 100000;
const long long MAXN = 2005;

int n, a, b;
struct cow {
    int p;
    int c;
    int x;
    cow(){
        p = 0;
        c = 0;
        x = 0;
    }
    cow (int p_, int c_, int x_){
        p = p_;
        c = c_;
        x = x_;
    }
};

vector<cow> v;
int dp[MAXN][2 * MAXN];

bool operator<(cow const& cx, cow const& cy){
    if(cx.x != cy.x) return cx.x < cy.x;
    return (cx.p / (double) cx.c) > (cy.p / (double) cy.c);
}

int main(){
    FAST;
    cin >> n >> a >> b;
    for(int i = 0; i < n; i++){
        int p, c, x;
        cin >> p >> c >> x;
        v.push_back(cow(p, c, x));
    }
    sort(v.begin(), v.end());
    memset(dp, -1, sizeof dp);
    dp[0][a + b] = 0;
    for(int i = 0; i < n; i++){
        int p = v[i].p;
        int c = v[i].c;
        int x = v[i].x;
        for(int j = 0; j <= a + b; j++){
            if(dp[i][j] == -1) continue;
            dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
            if(j >= a + c * x){
                dp[i + 1][j - c * x] = max(dp[i + 1][j - c * x], dp[i][j] + p);
            }
            else if(j > a){
                int red = (j - a) / x;
                if(a >= (c - red)){
                    dp[i + 1][a - (c - red)] = max(dp[i + 1][a - (c - red)], dp[i][j] + p);
                }
            }
            else if(j >= c){
                dp[i + 1][j - c] = max(dp[i + 1][j - c], dp[i][j] + p);
            }
        }
    }
    int maxe = 0;
    for(int i = 0; i <= a + b; i++){
        maxe = max(maxe, dp[n][i]);
    }
    cout << maxe << "\n";
}