function HashMap() {
let KEYS = [];
let VALUES = [];

this.isEmpty = function isEmpty() {
return KEYS.length === 0;
};

this.containsKey = function containsKey(key) {
let i = 0;
for (i = 0; i < KEYS.length; i++) {
if (KEYS[i] === key) {
return true;
}
}
return false;
};

this.containsValue = function containsValue(value) {
let i = 0;
for (i = 0; i < VALUES.length; i++) {
if (VALUES[i] === value) {
return true;
}
}
return false;
};

this.put = function put(key, value) {
let flag = false;
let i = 0;
for (i = 0; i < VALUES.length; i++) {
if (KEYS[i] === key) {
KEYS[i] = key;
VALUES[i] = value;
flag = true;
}
}
if (!flag) {
KEYS.push(key);
VALUES.push(value);
}
};

this.get = function get(key) {
let i = 0;
for (i = 0; i < VALUES.length; i++) {
if (KEYS[i] === key) {
return VALUES[i];
}
}
return null;
};

this.remove = function remove(key) {
let i = 0;
for (i = 0; i < VALUES.length; i++) {
if (KEYS[i] === key) {
KEYS.splice(i, 1);
VALUES.splice(i, 1);
return;
}
}
};

this.values = function values() {
const _VALUES = [];
let i = 0;
for (i = 0; i < VALUES.length; i++) {
_VALUES.push(VALUES[i]);
}
return _VALUES;
};

this.keySet = function keySet() {
const _KEYS = [];
let i = 0;
for (i = 0; i < KEYS.length; i++) {
_KEYS.push(KEYS[i]);
}
return _KEYS;
};

this.size = function size() {
return KEYS.lenth;
};

this.clear = function clear() {
KEYS = [];
VALUES = [];
};
}

export default HashMap;

// 參考文獻：http://www.cnblogs.com/chunyansong/p/5485759.html?spm=a1z2e.8028000.0.0.UAtnWF