var TEST = function () {
    
    var _time = 0;
    var _centers = [];
    var _maxSize = 1;
    
    function _print(arr, index) {
        console.log(arr.substr(index - _maxSize, _maxSize * 2 + 1));
    }
    
    function _MatchTest(arr, index) {
        if (!_isMatch(arr, index, _maxSize)) {
            return;
        }

        // 邊界比對相等，執行內部比對
        if (!_isInnerMatch(arr, index)) {
            return;
        }
        
        // 內部比對相等，擴大邊界比對
        var isUpdateRecord = false;
        var newMaxSize = _maxSize + 1;
        while (_isMatch(arr, index, (_maxSize + 1))) {
            _time++;
            isUpdateRecord = true;
            _maxSize++;
        }
        _centers = isUpdateRecord ? [index] : _centers;
    }
    
    
    function _isMatch(arr, index, size) {
        if (!arr[index-size] || !arr[index+size]) {
            return false; 
        }
        return arr[index-size] === arr[index+size];
    }
    
    function _isInnerMatch(arr, index) {
        var size = _maxSize - 1;
        while (size > 0) {
            _time++;
            if (!_isMatch(arr, index, size)) {
                return false;
            }
            size--;
        }
        _centers.push(index);
        return true;
    }
    
    function _reset() {
        _time = 0;
        _centers = [];
        _maxSize = 1;
    }
    
    return {
        doTest: function (str) {
            if (!str) { return; }
            _reset();
            var slen = str.length;
            for (var i=1; i<slen; i++) {
                _time++;
                _MatchTest(str, i);
            }
            
            var clen = _centers.length;
            for (var i=0; i<clen; i++) {
                _print(str, _centers[i]);
            }
            return _time;
        }
    };
}();

TEST.doTest('abebfdadgdaer');
TEST.doTest('abcscsbaaaadje');