You are given n pairs of numbers. In every pair, the first number is always smaller than the second number.
Now, we define a pair (c, d) can follow another pair (a, b) if and only if b < c. Chain of pairs can be formed in this fashion.
Given a set of pairs, find the length longest chain which can be formed. You needn't use up all the given pairs. You can select pairs in any order.
Example 1:
Input: [[1,2], [2,3], [3,4]]
Output: 2
Explanation: The longest chain is [1,2] -> [3,4]
Note:
- The number of given pairs will be in the range [1, 1000].
Runtime: 48 ms, faster than 63.85% of C++ online submissions for Maximum Length of Pair Chain.
排序然后two pointer。争取一次AC。
class Solution {
public:
static bool cmp(const vector<int>& a, const vector<int>& b){
return a[1] < b[1];
}
int findLongestChain(vector<vector<int>>& pairs) {
sort(pairs.begin(),pairs.end(),cmp);
int ret = 0, i = 0,j = 1;
while(j < pairs.size()){
if(pairs[i][1] < pairs[j][0]){
ret++;
i = j;
j++;
}else j++;
}
return ret+1;
}
};