Problem Link - Chef Rainfall Forecast
Problem Statement:
The chef, an avid lover of rain, eagerly anticipates the daily weather forecast. Given an array of integers rainfall representing the forecasted daily rainfall in millimeters for the next N days, Chef wants to know how many days he has to wait after the i-th day to experience a day with heavier rainfall. Help Chef by returning an array answer such that answer[i] is the number of days Chef has to wait after the i-th day to get a day with heavier rainfall. If there is no future day with heavier rainfall, keep answer[i] equal to 0 instead.
Approach:
The key idea is to use a stack to keep track of the days while we search for days with more rainfall. We start with an answer array filled with zeros to hold our results.
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Initialization: Create an answer array with zeros.
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Iteration: Loop through each day:
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If the current day’s rainfall is greater than the rainfall of the day at the top of the stack:
- Pop the index from the stack.
- Calculate how many days have passed since that day and store this value in the answer array.
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If the current day’s rainfall is not greater, push the current day’s index onto the stack.
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Efficiency: This method helps us quickly find how many days until a higher rainfall day while keeping the order of the days.
Time Complexity:
O(N): Each day is pushed and popped from the stack at most once, so the total time complexity is linear with respect to the number of days.
Space Complexity:
O(N): The space complexity is linear due to the storage required for the stack and the answer array.