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739. Daily Temperatures

Description

Given an array of integers temperatures represents the daily temperatures, return an array answer such that answer[i] is the number of days you have to wait after the ith day to get a warmer temperature. If there is no future day for which this is possible, keep answer[i] == 0 instead.

 

Example 1:

Input: temperatures = [73,74,75,71,69,72,76,73]
Output: [1,1,4,2,1,1,0,0]

Example 2:

Input: temperatures = [30,40,50,60]
Output: [1,1,1,0]

Example 3:

Input: temperatures = [30,60,90]
Output: [1,1,0]

 

Constraints:

  • 1 <= temperatures.length <= 105
  • 30 <= temperatures[i] <= 100

Solutions

Solution 1

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class Solution:
    def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
        ans = [0] * len(temperatures)
        stk = []
        for i, t in enumerate(temperatures):
            while stk and temperatures[stk[-1]] < t:
                j = stk.pop()
                ans[j] = i - j
            stk.append(i)
        return ans

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class Solution {
    public int[] dailyTemperatures(int[] temperatures) {
        int n = temperatures.length;
        int[] ans = new int[n];
        Deque<Integer> stk = new ArrayDeque<>();
        for (int i = 0; i < n; ++i) {
            while (!stk.isEmpty() && temperatures[stk.peek()] < temperatures[i]) {
                int j = stk.pop();
                ans[j] = i - j;
            }
            stk.push(i);
        }
        return ans;
    }
}

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class Solution {
public:
    vector<int> dailyTemperatures(vector<int>& temperatures) {
        int n = temperatures.size();
        vector<int> ans(n);
        stack<int> stk;
        for (int i = 0; i < n; ++i) {
            while (!stk.empty() && temperatures[stk.top()] < temperatures[i]) {
                ans[stk.top()] = i - stk.top();
                stk.pop();
            }
            stk.push(i);
        }
        return ans;
    }
};

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func dailyTemperatures(temperatures []int) []int {
    ans := make([]int, len(temperatures))
    var stk []int
    for i, t := range temperatures {
        for len(stk) > 0 && temperatures[stk[len(stk)-1]] < t {
            j := stk[len(stk)-1]
            ans[j] = i - j
            stk = stk[:len(stk)-1]
        }
        stk = append(stk, i)
    }
    return ans
}

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function dailyTemperatures(temperatures: number[]): number[] {
    const n = temperatures.length;
    const ans = new Array(n).fill(0);
    const stk: number[] = [];
    for (let i = n - 1; i >= 0; --i) {
        while (stk.length && temperatures[stk[stk.length - 1]] <= temperatures[i]) {
            stk.pop();
        }
        if (stk.length) {
            ans[i] = stk[stk.length - 1] - i;
        }
        stk.push(i);
    }
    return ans;
}

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impl Solution {
    pub fn daily_temperatures(temperatures: Vec<i32>) -> Vec<i32> {
        let n = temperatures.len();
        let mut stack = vec![];
        let mut res = vec![0; n];
        for i in 0..n {
            while !stack.is_empty() && temperatures[*stack.last().unwrap()] < temperatures[i] {
                let j = stack.pop().unwrap();
                res[j] = (i - j) as i32;
            }
            stack.push(i);
        }
        res
    }
}

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/**
 * @param {number[]} temperatures
 * @return {number[]}
 */
var dailyTemperatures = function (temperatures) {
    const n = temperatures.length;
    const ans = new Array(n).fill(0);
    const stk = [];
    for (let i = n - 1; i >= 0; --i) {
        while (stk.length && temperatures[stk[stk.length - 1]] <= temperatures[i]) {
            stk.pop();
        }
        if (stk.length) {
            ans[i] = stk[stk.length - 1] - i;
        }
        stk.push(i);
    }
    return ans;
};

Solution 2

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class Solution:
    def dailyTemperatures(self, temperatures: List[int]) -> List[int]:
        n = len(temperatures)
        stk = []
        ans = [0] * n
        for i in range(n - 1, -1, -1):
            while stk and temperatures[stk[-1]] <= temperatures[i]:
                stk.pop()
            if stk:
                ans[i] = stk[-1] - i
            stk.append(i)
        return ans

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class Solution {
    public int[] dailyTemperatures(int[] temperatures) {
        int n = temperatures.length;
        Deque<Integer> stk = new ArrayDeque<>();
        int[] ans = new int[n];
        for (int i = n - 1; i >= 0; --i) {
            while (!stk.isEmpty() && temperatures[stk.peek()] <= temperatures[i]) {
                stk.pop();
            }
            if (!stk.isEmpty()) {
                ans[i] = stk.peek() - i;
            }
            stk.push(i);
        }
        return ans;
    }
}

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class Solution {
public:
    vector<int> dailyTemperatures(vector<int>& temperatures) {
        int n = temperatures.size();
        vector<int> ans(n);
        stack<int> stk;
        for (int i = n - 1; ~i; --i) {
            while (!stk.empty() && temperatures[stk.top()] <= temperatures[i]) stk.pop();
            if (!stk.empty()) ans[i] = stk.top() - i;
            stk.push(i);
        }
        return ans;
    }
};

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func dailyTemperatures(temperatures []int) []int {
    n := len(temperatures)
    ans := make([]int, n)
    var stk []int
    for i := n - 1; i >= 0; i-- {
        for len(stk) > 0 && temperatures[stk[len(stk)-1]] <= temperatures[i] {
            stk = stk[:len(stk)-1]
        }
        if len(stk) > 0 {
            ans[i] = stk[len(stk)-1] - i
        }
        stk = append(stk, i)
    }
    return ans
}

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