LeetCode || Max Points on a Line

/**
 * Definition for a point.
 * struct Point {
 *     int x;
 *     int y;
 *     Point() : x(0), y(0) {}
 *     Point(int a, int b) : x(a), y(b) {}
 * };
 */
class Solution {
public:
    int maxPoints(vector<Point> &points) {
        unordered_map<double, int> umap;
        int res=0;
        int len=points.size();
        if(len>0){
            for(int i=0; i<len; ++i){
                int samepoints=0;
                umap.clear();
                int tempres=1;
                for(int j=i+1; j<len; ++j){
                    double slope=numeric_limits<double>::infinity();
                    int dx=points[i].x-points[j].x;
                    int dy=points[i].y-points[j].y;
                    if(dx==0){
                        if(dy==0){
                            samepoints++;
                            if(res<samepoints)
                                res=samepoints;
                            continue;
                        }
                    }
                    else{
                        slope=1.0*dy/dx;
                    }
                    if(umap.find(slope)!=umap.end()){
                        umap[slope]++;
                    }
                    else{
                        umap.insert(unordered_map<double, int>::value_type(slope, 2));
                    }
                    if(tempres<umap[slope])
                        tempres=umap[slope];
                }
                if(res<tempres+samepoints)
                        res=tempres+samepoints;
            }
        }
        return res;
    }
};

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LeetCode || Max Points on a Line

原文：http://blog.csdn.net/jiadebin890724/article/details/23303115