# | 제출 시각 | 아이디 | 문제 | 언어 | 결과 | 실행 시간 | 메모리 |
---|---|---|---|---|---|---|---|
1141213 | harry_tm_18 | Jobs (BOI24_jobs) | C++20 | 0 ms | 0 KiB |
#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;
struct Job {
int profit;
int prerequisite;
};
int main() {
int N, s;
cin >> N >> s;
vector<Job> jobs(N + 1); // Jobs are indexed from 1 to N
vector<vector<int>> adj(N + 1); // Adjacency list for dependencies
vector<int> inDegree(N + 1, 0); // In-degree for topological sorting
for (int i = 1; i <= N; i++) {
cin >> jobs[i].profit >> jobs[i].prerequisite;
if (jobs[i].prerequisite != 0) {
adj[jobs[i].prerequisite].push_back(i);
inDegree[i]++;
}
}
// Topological sort using Kahn's algorithm
queue<int> q;
vector<int> topoOrder;
for (int i = 1; i <= N; i++) {
if (inDegree[i] == 0) {
q.push(i);
}
}
while (!q.empty()) {
int cur = q.front();
q.pop();
topoOrder.push_back(cur);
for (int neighbor : adj[cur]) {
inDegree[neighbor]--;
if (inDegree[neighbor] == 0) {
q.push(neighbor);
}
}
}
// DP to calculate the maximum profit
vector<int> dp(N + 1, INT_MIN); // dp[i] = max profit achievable ending with job i
dp[0] = s; // Initial money
for (int job : topoOrder) {
if (dp[jobs[job].prerequisite] >= 0) { // Ensure prerequisite job can be completed
dp[job] = max(dp[job], dp[jobs[job].prerequisite] + jobs[job].profit);
}
}
// Find the maximum profit achievable
int maxProfit = 0;
for (int i = 1; i <= N; i++) {
maxProfit = max(maxProfit, dp[i]);
}
cout << maxProfit - s << endl; // Subtract initial money to get the profit
return 0;
}