Random Sudoku board generator

[d_stranz]

for (int i = 0;i < 80; i++){
        for (int j = 0;j < 20; j++){
            if (random_pos_value[j].first == i){
                tiles[i]->setText(QString::number(random_pos_value[j].second));
                tiles[i]->setReadOnly(true);
            }
        }
    }

for (int i = 0;i < 80; i++){
        for (int j = 0;j < 20; j++){
            if (random_pos_value[j].first == i){
                tiles[i]->setText(QString::number(random_pos_value[j].second));
                tiles[i]->setReadOnly(true);
            }
        }
    }

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Think about this loop. The innermost part of it runs 3200 times. Is that what you want to do?