[leetcode 139] Word Break

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.

For example, given

s =

"leetcode"

,

dict =

["leet", "code"]

.

Return true because

"leetcode"

can be segmented as

"leet
code"

.

class Solution {
public:
bool wordBreak(string s, unordered_set<string> &dict) {
const int n = s.size();
bool f[n+1];
fill_n(&f[0], n+1, false);
f[0] = true;
for (int i = 1; i <= n; i++) {
for (int j = i - 1; j >= 0; j--) {
if (f[j] && dict.find(s.substr(j, i-j)) != dict.end()) {
f[i] =  true;
break;
}
}
}
return f
;
}
};