array 2 map

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Longest Consecutive Sequence

差一点就可以想到了，想到一个数，然后他的左右值，想到map但是，没想到一直查找下去，以为添加并修改就可以了，结果不能保证连续性，实际上，是每次都计算当前值得长度，并保存最大的长度。

class Solution {public:    int longestConsecutive(vector<int> &num) {    if(num.empty())return -1;map<int,bool> usedmap;    for(auto i :num)        usedmap[i] = false;        int longest = 0;        for(auto i : num)    {        if(usedmap[i])            continue;        int length = 1;                usedmap[i] = true;        for(int j = i + 1; usedmap.end() != usedmap.find(j); ++ j )        {            usedmap[j] = true;            ++ length;        }                for(int j = i - 1; usedmap.end() != usedmap.find(j); -- j )        {            usedmap[j] = true;            ++ length;        }                longest = max(longest,length);    }    return longest;    }};

Two Sum

回头看之前做的twosum发现自己的思路就很怪，干嘛要排序呢，思路方向错了，就错得很离谱，做出的结果也复杂

class Solution {public:    vector<int> twoSum(vector<int> &numbers, int target) {        map<int,int> mymap;vector<int> index;int index1,index2;index1 = index2 = 0;for(vector<int>::size_type i = 0; i != numbers.size(); ++ i ){if(mymap.empty())mymap[numbers[i]] = i;else{if(mymap.end() != mymap.find(target - numbers[i])){index1 = mymap.find(target - numbers[i])->second+1;index2 = i+1;break;}elsemymap[numbers[i]] = i;}}index.push_back(index1);index.push_back(index2);return index;    }};

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