56 lines
888 B
JavaScript
56 lines
888 B
JavaScript
export function mod_exp(a, b, n) {
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let res = 1n;
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while (b > 0n) {
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if (b % 2n === 1n) {
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res = (res * a) % n;
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}
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b >>= 1n;
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a = (a * a) % n;
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}
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return res;
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}
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export function mod_inv(a, n) {
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let t = 0n;
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let new_t = 1n;
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let r = n;
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let new_r = a;
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while (new_r !== 0n) {
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let quotient = r / new_r;
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let t_temp = t;
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t = new_t;
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new_t = t_temp - quotient * new_t;
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let r_temp = r;
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r = new_r;
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new_r = r_temp - quotient * new_r;
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}
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if (t < 0) {
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t = t + n;
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}
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return t;
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}
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export function gcd(a, b) {
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// check a, b are correct types.
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a *= 1n;
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b *= 1n;
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while (b !== 0n) {
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let temp = b;
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b = a % b;
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a = temp;
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}
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return a;
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}
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window.mod_exp = mod_exp;
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window.mod_inv = mod_inv;
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window.gcd = gcd;
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