34 lines
852 B
C++
34 lines
852 B
C++
#include "all_includes.hh"
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int random_seed() {
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static bool initialized = false;
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if (!initialized) {
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initialized = true;
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srand(time(NULL));
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}
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return rand();
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}
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// Ce hash donne des bons résultats sur tous les bits de l'entier
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// généré (pas d'artefacts, répartition homogène des 0 et des 1).
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unsigned int hash2(unsigned int a, unsigned int b) {
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unsigned int h = 1;
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int i;
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for (i = 0; i < 32; i+=8) {
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a = a*h + 1;
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b = b*h + 1;
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// marche aussi avec 65521.
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h = (h << 6) + (h << 16) - h + ((a >> i) & 0xff); // h * 65599 + ieme octet de a
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h = (h << 6) + (h << 16) - h + ((b >> i) & 0xff); // h * 65599 + ieme octet de b
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}
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return h;
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}
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int hashInRange(int seed, int n, int a, int b) {
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return (hash2(seed, n) % (b - a)) + a;
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}
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bool proba(int seed, int n, unsigned int a, unsigned int b) {
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return ((hash2(seed, n) % b) < a);
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}
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