Med670.java

//maximum swap


    class Med670 {
        public int maximumSwap(int num) {
            char numArr[] = Integer.toString(num).toCharArray();
            int n = numArr.length;
            char maxElement = numArr[n-1]; 
            int maxIndex = n-1;
            int swapIdx1 = -1;
            int swapIdx2 = -1;
            for(int i=n-2;i>=0;i--){
                if(numArr[i] > maxElement){
                    maxElement = numArr[i];
                    maxIndex = i;
                }else if(numArr[i] < maxElement){
                    swapIdx1 = i;
                    swapIdx2 = maxIndex;
                }
            }
    
            //perform swapping
            if(swapIdx1!=-1){
                char temp = numArr[swapIdx1];
                numArr[swapIdx1] = numArr[swapIdx2];
                numArr[swapIdx2] = temp;
            }
            return Integer.parseInt(new String(numArr));
            
        }
    }