53.最大子数组和
文章目录
题目描述:
解法:动态规划
代码:
class Solution {
public int maxSubArray(int[] nums) {
int len = nums.length;
/*
1.dp[i] 表示以下标i结尾的最大连续子数组和
2.if(dp[i - 1] > 0){
dp[i] = dp[i - 1] + nums[i];
} else {
dp[i] = nums[i];
}
3. dp[i] = nums[i];
*/
int[] dp = new int[len];
int rest = nums[0];
dp[0] = nums[0];
for(int i = 1; i < len; i++){
if(dp[i - 1] > 0){
dp[i] = dp[i - 1] + nums[i];
} else {
dp[i] = nums[i];
}
rest = Math.max(rest, dp[i]);
}
return rest;
}
}
优化
代码:
class Solution {
public int maxSubArray(int[] nums) {
int len = nums.length;
int[] dp = new int[len];
int rest = nums[0], m = rest;//两个变量表示最大和
dp[0] = nums[0];
for(int i = 1; i <len; i++){
m = Math.max(m + nums[i], nums[i]);
if(m > rest){
rest = m;
}
}
return rest;
}
}