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// 1345. Jump Game IV
#include "leetcode.h"
/*
* given array of integers 'arr', you are initially positioned at first index of
* array. in one step, you can jump from index 'i' to index 'j'. return minimum
* number of steps to reach lat index of array. notice, you cannot jump outside
* of array at any time.
*/
class Solution {
public:
int minJumps(vector<int> &arr) {
int n = arr.size(), step = 0;
unordered_map<int, vector<int>> idx_val;
for (int i = 0; i < n; i++)
idx_val[arr[i]].push_back(i);
vector<bool> visited(n);
visited[0] = true;
queue<int> q;
q.push(0);
while (!q.empty()) {
for (int size = q.size(); size > 0; --size) {
int i = q.front();
q.pop();
if (i == n - 1)
return step; // end of arr
vector<int> next = idx_val[arr[i]];
next.push_back(i - 1);
next.push_back(i + 1);
for (int j : next) {
if (j >= 0 && j < n && !visited[j]) {
visited[j] = true;
q.push(j);
}
}
next.clear();
}
step++;
}
return 0;
}
};
int main() {
Solution obj;
vector<int> a1 = {100, -23, -23, 404, 100, 23, 23, 23, 3, 404};
vector<int> a2 = {7}, a3 = {7, 6, 9, 6, 9, 6, 9, 7};
cout << obj.minJumps(a1) << endl; // expect: 3
cout << obj.minJumps(a2) << endl; // expect: 0
cout << obj.minJumps(a3) << endl; // expect: 1
}
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