740. 删除并获得点数
解法一: 序列dp
class Solution {
int count[]= new int[10001];
public int deleteAndEarn(int[] nums) {
int max =0;
int n=nums.length;
if(n==0) return 0;
for (int x : nums) {
count[x]++;
max = Math.max(max,x);
}
int [][]dp = new int [max+1][2];
for(int i=1;i<=max;i++){
dp[i][0] = Math.max(dp[i-1][0],dp[i-1][1]);
dp[i][1] = dp[i-1][0]+i*count[i];
}
return Math.max(dp[max][0],dp[max][1]);
}
解法二:
public int deleteAndEarn(int[] nums) {
if (nums == null || nums.length == 0) {
return 0;
} else if (nums.length == 1) {
return nums[0];
}
int len = nums.length;
int max = nums[0];
for (int i = 0; i < len; ++i) {
max = Math.max(max, nums[i]);
}
// 构造一个新的数组all
int[] all = new int[max + 1];
for (int item : nums) {
all[item] ++;
}
int[] dp = new int[max + 1];
dp[1] = all[1] * 1;
dp[2] = Math.max(dp[1], all[2] * 2);
// 动态规划求解
for (int i = 2; i <= max; ++i) {
dp[i] = Math.max(dp[i - 1], dp[i - 2] + i * all[i]);
}
return dp[max];
}