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/* | |
Mercer 2018 Problem 10: Nth Derivative. | |
Charles Bailey. 03/01/2018 | |
*/ | |
#include <bits/stdc++.h> | |
#include <regex> | |
typedef long long ll; | |
struct term { | |
bool neg; | |
ll coeff; | |
ll power; | |
std::string to_string(const bool& first) { | |
std::stringstream ret; | |
if (coeff == 0) return ""; | |
if (neg) | |
ret << "-"; | |
else if (!first) | |
ret << "+"; | |
if (coeff > 1 || power == 0) | |
ret << coeff; | |
if (power != 0 && coeff > 1) | |
ret << "*x"; | |
else if (power != 0) | |
ret << "x"; | |
if (power > 1 || power < 0) | |
ret << "^" << power; | |
return ret.str(); | |
} | |
}; | |
static void one_case(void) { | |
const std::regex PATTERN{"(\\+|-)?(\\d*)\\*?(x?((?:\\^)-?\\d+)?)"}; | |
ll n; | |
std::scanf("%lld",&n); | |
std::string str; | |
std::cin >> str; | |
std::smatch sm; | |
bool first = true; | |
while (std::regex_search(str, sm, PATTERN) && !sm[0].str().empty()) { | |
term tmp = {sm[1] == "-", sm[2].str().empty() ? 1 : std::stoi(sm[2].str()), | |
sm[4].str().empty() && sm[3].str().empty() ? 0 : (sm[4].str().empty() ? 1 : std::stoi(sm[4].str().substr(1)))}; | |
for (ll i = 1; i <= n; ++i) { | |
tmp.coeff *= tmp.power--; | |
if (tmp.coeff < 0) | |
tmp.neg = !tmp.neg; | |
tmp.coeff = std::abs(tmp.coeff); | |
} | |
std::printf("%s", tmp.to_string(first).data()); | |
first = false; | |
str = sm.suffix(); | |
} | |
std::putchar('\n'); | |
} | |
int main(void) { | |
ll t; | |
std::scanf("%lld", &t); | |
while(t--) one_case(); | |
return 0; | |
} |
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