Daily Temperatures

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Given a list of daily temperatures T, return a list such that, for each day in the input, tells you how many days you would have to wait until a warmer temperature. If there is no future day for which this is possible, put 0 instead.

For example, given the list of temperatures 

T = [73, 74, 75, 71, 69, 72, 76, 73], 
your output should be [1, 1, 4, 2, 1, 1, 0, 0].

Note: 

  • The length of temperatures will be in the range [1, 30000].
  • Each temperature will be an integer in the range [30, 100].
class Solution {
    public int[] dailyTemperatures(int[] T) {
        
        int n = T.length;
        int[] result = new int[n];
        Stack<Integer> stack = new Stack<>();
        for(int i = n-1 ; i >= 0 ; i--){
            int cur_temp = T[i];
            while(!stack.isEmpty() && cur_temp >= T[stack.peek()]){
                stack.pop();
            }
            result[i] = stack.isEmpty() ? 0 : stack.peek() - i;
            stack.push(i);
        }
        return result;
    }
}

The ouput of the given array will be calculated as:

 T = [73, 74, 75, 71, 69, 72, 76, 73]
     [1,  1,  4,  2,  1,  1,   0,  0]

Categories: Stack

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