Question

How to check if the last index of a vector is reachable by jumping based on element values from index 0 in C++

Answer 1

#include <iostream>
#include <vector>

bool canReachLastIndex(std::vector<int>& vec) {
    int size = vec.size();
    int currentIndex = 0;

    while (currentIndex < size) {
        // If we reach the last index, return true
        if (currentIndex == size - 1) return true;

        // If jump goes out of bounds, stop
        if (currentIndex + vec[currentIndex] >= size) return false;

        // Move to the next index by jumping
        currentIndex += vec[currentIndex];
    }

    return false;
}

int main() {
    std::vector<int> vec = {2, 3, 1, 1, 4}; 
    
    if (canReachLastIndex(vec)) {
        std::cout << "Yes, we can reach the last index." << std::endl;
    } else {
        std::cout << "No, we cannot reach the last index." << std::endl;
    }
}



/*
run:

Yes, we can reach the last index.

*/

 

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