【leetcode】1232. 缀点成线

bool checkStraightLine(int** coordinates, int coordinatesSize, int* coordinatesColSize){
    float a=0,b;
    int i;
    for(i=0; i<coordinatesSize-1; i++){
        if(coordinates[i][0] != coordinates[i+1][0]){
            a=(float)(coordinates[i+1][1]-coordinates[i][1])/(coordinates[i+1][0]-coordinates[i][0]);
            b=coordinates[i][1]-coordinates[i][0]*a;
            break;
        }
    }
    if(i==coordinatesSize-1) return true;
    for(i=1; i<coordinatesSize; i++){
        if(a*coordinates[i][0]+b != coordinates[i][1])
            return false;
    }
    return true;
}