set grid
do for [i=1:5] {
    set term pngcairo size 800,600

    unset logscale
    set output sprintf("alg%d.png", i)
    plot sprintf("alg%d.txt", i) with linespoints title sprintf("Algoritmo %d", i)
    unset output

    set logscale y
    set output sprintf("alg%d_log.png", i)
    plot sprintf("alg%d.txt", i) with linespoints title sprintf("Algoritmo %d", i)
    unset output

    set logscale x
    set logscale y
    set output sprintf("alg%d_loglog.png", i)
    plot sprintf("alg%d.txt", i) with linespoints title sprintf("Algoritmo %d", i)
    unset output

    unset logscale
}