void histogramEqualization(Mat src){
    int height = src.rows;
    int width = src.cols;
    int M = height*width;
    int* h = computeHistogram(src);
    Mat dest = src.clone();
    int L = 255;

    float* p = (float*) malloc(256 * sizeof(float));
    float* pc = (float*) malloc(256 * sizeof(float));
    for(int i = 0; i < 256; i++){
        p[i] = h[i]/((float)M);
        for(int k = 0; k <= i; k++){
            pc[i] += p[k];
        }
    }

    for(int i = 0; i < height; i++){
        for(int j = 0; j < width; j++){
            int gout = L*pc[src.at<unsigned char>(i, j)];
            dest.at<unsigned char>(i, j) = gout;
        }
    }
    imshow("src", src);
    imshow("dest", dest);
    showHistogram("srcHist", computeHistogram(src), 256, 500);
    showHistogram("destHist", computeHistogram(dest), 256, 500);
    waitKey();
}