Leecode 343.整数拆分
class Solution {
public:
int integerBreak(int n) {
// dp[i]代表i能拆分得到的最大乘积
vector<int> dp(n + 1, 0);
// 初始化
dp[1] = 1;
dp[2] = 1;
// 状态转移方程:dp[i] = max(j * i - j, j * dp[i - j])
for (int i = 3; i <= n; ++i) {
for (int j = 1; j < i; ++j) {
dp[i] = max(dp[i], max(j * (i - j), j * dp[i - j]));
}
}
return dp[n];
}
};
Leecode 96.不同的二又搜索树
class Solution {
public:
int numTrees(int n) {
// 代表当有i个节点时,有几种组合
vector<int> dp(n + 1, 0);
dp[0] = 1;
dp[1] = 1;
// 状态转移:dp[i] = dp[0] * dp[i - 1] + ...... + dp[i - 1] * dp[0]
for (int i = 2; i <= n; ++i) {
for (int j = 0; j < i; ++j) {
dp[i] += dp[j] * dp[i - j - 1];
}
}
return dp[n];
}
};