路漫漫其修远,我将上下而求索。
**自今日始,开启程序员修炼之路,不可一日之懈怠。leetcode每日刷一道算法题以及每日博客写当日修炼心得。**
今天,刷了第一题,出现了很多粗浅的错误,用惯了IDE,发现自己手写代码没提示的情况下很low,这使我很是羞愧,方法和属性傻傻分不清,数组的长度是属性length而非length();对数组进行循环嵌套遍历时,对index考虑不够周到,很大意的出现了越界错误,警惕之,对一道题的考虑不够全面,实现过于单一,思路狭隘,要加以改进。贴上今日代码,铭记。
public int[] twoSum(int[] nums, int target) {
int temp = 0;
for(int i = 0; i < nums.length - 1; i++) {
for (int j = i + 1; j < nums.length ; j ++) {
if (nums[i] != nums [j]) {
temp = nums[i] + nums[j];
if (target == temp) {
return new int[]{i,j};
}
}
}
}
return null;
}
throw应该改为throw new IllegalArgumentException("No two sum solution");
看官方的解答,哈希表HashMap不失为一种好方法!!!
public int[] twoSum(int[] nums, int target) {
Map<Integer, Integer> map = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
map.put(nums[i], i);
}
for (int i = 0; i < nums.length; i++) {
int complement = target - nums[i];
if (map.containsKey(complement) && map.get(complement) != i) {
return new int[] { i, map.get(complement) };
}
}
throw new IllegalArgumentException("No two sum solution");
}
public int[] twoSum(int[] nums, int target) {
Map<Integer, Integer> map = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
int complement = target - nums[i];
if (map.containsKey(complement)) {
return new int[] { map.get(complement), i };
}
map.put(nums[i], i);
}
throw new IllegalArgumentException("No two sum solution");
}