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Leetcode139.cpp
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92 lines (85 loc) · 2.75 KB
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// Leetcode139.cpp : This file contains the 'main' function. Program execution begins and ends there.
//
#include <iostream>
unordered_map<string, int> mapStr;
bool wordBreak(string s, vector<string>& wordDict) {
if (s.empty()) return true;
if (mapStr.find(s) != mapStr.end())
{
if (mapStr[s] == 1) return true;
if (mapStr[s] == 0) return false;
}
for (auto& word : wordDict)
{
if (s[0] == word[0] && s.find(word) == 0)
{
mapStr[word] = 1;
string rightSubStr = s.substr(word.size());
if (wordBreak(rightSubStr, wordDict))
{
mapStr[s] = 1;
return true;
}
else
{
mapStr[rightSubStr] = 0;
//return false;
}
}
}
return false;
}
class Solution {
private:
bool wordBreak(string s, unordered_set<string>& set, vector<int>& memo, int start) {
if (start == s.size()) {
return true;
}
if (memo[start] != -1) {
return memo[start];
}
for (int i = start; i < s.size(); i++) {
if (set.count(s.substr(start, i + 1 - start)) && wordBreak(s, set, memo, i + 1)) {
memo[start] = true;
return true;
}
}
return memo[start] = false;
}
public:
bool wordBreak(string s, vector<string>& wordDict) {
vector<int> memo(s.size(), -1);
unordered_set<string> set(wordDict.begin(), wordDict.end());
return wordBreak(s, set, memo, 0);
}
};
class Solution {
public:
bool wordBreak(string s, vector<string>& wordDict) {
vector<bool> dp(s.size() + 1, 0);
dp[0] = true;
unordered_set<string> set(wordDict.begin(), wordDict.end());
for (int i = 1; i <= s.size(); i++) {
for (int j = 0; j < i; j++) {
if (dp[j] && set.count(s.substr(j, i - j))) {
dp[i] = true;
break;
}
}
}
return dp[s.size()];
}
};
int main()
{
std::cout << "Hello World!\n";
}
// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu
// Tips for Getting Started:
// 1. Use the Solution Explorer window to add/manage files
// 2. Use the Team Explorer window to connect to source control
// 3. Use the Output window to see build output and other messages
// 4. Use the Error List window to view errors
// 5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
// 6. In the future, to open this project again, go to File > Open > Project and select the .sln file