Frog and flies

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    cin >> n;

    vector<int> a(n + 1);
    vector<int> b(n + 1);
    vector<int> c(n + 1);
    
    for (int i = 1; i <= n; i++) {
        cin >> a[i] >> b[i] >> c[i];
    }
    
    vector<long long> dp(n + 2, 0);  // Use n + 2 to safely handle range updates
    
    // Initialize dp where we can start at any rock
    for (int i = 1; i <= n; i++) {
        dp[i] += a[i];  // Starting on this rock itself catches these many flies
    }
    
    // Prepare the range increment operations using the difference array technique
    for (int i = 1; i <= n; i++) {
        int start = b[i];
        int end = c[i];
        if (start > n) continue;  // No valid jump
        dp[start] += a[i];  // Increment at the start of the range
        dp[end + 1] -= a[i];  // Decrement right after the end of the range
    }
    
    // Apply the increments to compute the actual maximum flies we can catch
    long long max_flies = 0, current_flies = 0;
    for (int i = 1; i <= n; i++) {
        current_flies += dp[i];  // Accumulate the increment/decrement to get actual values
        max_flies = max(max_flies, current_flies);
    }

    cout << max_flies << endl;

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

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Test 3

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Test 4

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Test 5

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Test 6

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Test 8

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Test 9

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Test 10

Verdict: ACCEPTED

Test 11

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Test 12

Verdict: ACCEPTED

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Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED

Test 43

Verdict: ACCEPTED

Test 44

Verdict: ACCEPTED

Test 45

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 47

Verdict: ACCEPTED

Test 48

Verdict: ACCEPTED

Test 49

Verdict: ACCEPTED

Test 50

Verdict: ACCEPTED

Test 51

Verdict: ACCEPTED

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Verdict: ACCEPTED

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Verdict: ACCEPTED

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Test 55

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Verdict: ACCEPTED

Test 60

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 62

Verdict: ACCEPTED

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Verdict: ACCEPTED

Test 64

Verdict: ACCEPTED

Test 65

Verdict: ACCEPTED

Test 66

Verdict: ACCEPTED

Test 67

Verdict: ACCEPTED