1762. Buildings With an Ocean View

本文主要是介绍1762. Buildings With an Ocean View，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

My first solution is use two skacks, one stack store index, another one store value, the time complexity is O(n).

    public int[] findBuildings(int[] heights) {
        Stack<Integer> indexStk = new Stack<>();
        Stack<Integer> valueStk = new Stack<>();
        for(int i=heights.length-1;i>=0;i--){
            if(valueStk.isEmpty() || heights[i]>valueStk.peek()){
                indexStk.push(i);
                valueStk.push(heights[i]);
            }
        }
        int[] res = new int[indexStk.size()];
        int i=0;
        while(!indexStk.isEmpty()){
            res[i++]=indexStk.pop();
        }
        return res;
    }

The second stack, valueStk, can be replaced with an Integer.

    public int[] findBuildings(int[] heights) {
        int n = heights.length;
        Stack<Integer> indexStk = new Stack<>();
        int valueStk = heights[n-1];
        indexStk.push(n-1);
        for(int i=n-2;i>=0;i--){
            if(heights[i]>valueStk){
                indexStk.push(i);
                valueStk = heights[i];
            }
        }
        int[] res = new int[indexStk.size()];
        int i=0;
        while(!indexStk.isEmpty()){
            res[i++]=indexStk.pop();
        }
        return res;
    }

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