Leetcode #42

gistfile1.txt

    public int trap(int[] A) {
        int count = 0;
        int leftPeak = -1;
        int rightPeak = -1;
        int minPeak = -1;
        boolean flag = false;
        for(int i=0; i<A.length; i++){
            if(isPeak(A,i)){
                leftPeak = rightPeak;
                rightPeak = i;
                if(leftPeak == -1)
                    continue;
                else {
                    minPeak = Math.min(A[leftPeak],A[rightPeak]);
                    for(int j=leftPeak+1;j<rightPeak;j++){
                        if(A[j]<minPeak){
                            count += minPeak-A[j];
                            A[j]=minPeak;
                            flag = true;
                        }
                    }
                }
            }
        }
        if(flag){
            count+= trap(A);
        }
        return count;
    }
    public boolean isPeak(int[] A, int i){
        if(i==0){
            if(i==A.length-1)
                return false;
            else if(A[i]>A[i+1])
                return true;
        }else if(i==A.length-1){
            if(i==0)
                return false;
            else if(A[i]>A[i-1])
                return true;
        }else if(A[i-1]<=A[i] && A[i]>=A[i+1]){
            if(A[i-1] == A[i] && A[i] == A[i+1])
                return false;
            return true;
        }
        return false;
    }