Rotate the matrix anti-clockwise

rotate-matrix.js

/*
https://www.hackerrank.com/challenges/matrix-rotation-algo

You are given a 2D matrix, a, of dimension MxN and a positive integer R. 
You have to rotate the matrix R times and print the resultant matrix. 
Rotation should be in anti-clockwise direction.
*/
process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

var lines = [];
lineNo = 0;

process.stdin.on("end", function () {
    lines = _input.split('\n');
    solution();
});

function readLine(){
    return lines[lineNo++];
}

function solution(){
    var line = readLine();
    var tmp = line.split(' ');
    var M = tmp[0];
    var N = tmp[1];
    var R = tmp[2];
    
    var matrix = [];
    for (var i = 0; i < M; i++){
        line = readLine();
        matrix.push(line.split(' '));
    }
    
    rotate(matrix, M, N, R);
    print(matrix);
}

function print(matrix){
    for(var i=0; i< matrix.length; i++)
        console.log(matrix[i].join(' '));            
}

// rotate the matrix anti-clockwise R times
function rotate(matrix, M, N, R) {    
    // calculate how many circles we need to rotate
    var circles = ~~(Math.min(M, N) / 2);
    
    for(var i = 0; i < circles; i++){
        // eliminate unnecessary full circle rotations
        var circleLen = (M - i*2)*2 + (N - i*2 - 2)*2;
        var rotations = R % circleLen;
        
        for (var j = 0; j < rotations; j++)
        {
            rotateCircle(matrix, i, i);    
        }
    }
}

//[i,j]      [i, n-1-j]
//[m-1-i, j] [m-1-i, n-1-j]
//
function rotateCircle(matrix, i, j){
    var k, l;
    var m = matrix.length;
    var n = matrix[0].length;
    var tmp = matrix[i][j];
    
    for ( k = j+1; k <= n-1-j; k++ ){
        matrix[i][k-1] = matrix[i][k];
    }
    
    for ( k = i+1; k<= m-1-i; k++ ){
        //console.log('%s->%s', matrix[k][n-1-j], matrix[k-1][n-1-j])
        matrix[k-1][n-1-j] = matrix[k][n-1-j];
        
    }
    
    for ( k = n-1-j; k>j; k-- ) {
        //console.log('%s->%s', matrix[m-1-i][k-1], matrix[m-1-i][k])
        matrix[m-1-i][k] = matrix[m-1-i][k-1];
    }
    
    for ( k = m-1-i; k>i; k-- ) {
        matrix[k][j] = matrix[k-1][j];
    }
    
    matrix[i+1][j] = tmp;
}