cp/usaco/bronze/simulation/mowing.cc
2025-04-30 16:28:40 -04:00

101 lines
1.8 KiB
C++

#include <bits/stdc++.h> // {{{
// https://codeforces.com/blog/entry/96344
#pragma GCC optimize("O2,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
using namespace std;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;
using f64 = double;
using f128 = long double;
template <typename T>
constexpr T MIN = std::numeric_limits<T>::min();
template <typename T>
constexpr T MAX = std::numeric_limits<T>::max();
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define ff first
#define ss second
#ifdef LOCAL
#define db(...) std::print(__VA_ARGS__)
#define dbln(...) std::println(__VA_ARGS__)
#else
#define db(...)
#define dbln(...)
#endif
// }}}
void solve() {
i32 n;
cin >> n;
map<pair<i64, i64>, i64> m;
m[{0, 0}] = 0;
char dir;
i64 delta;
i64 x = 0, y = 0;
i64 ans = MAX<i64>, t = 0;
while (n--) {
cin >> dir >> delta;
i64 dx = 0, dy = 0;
switch (dir) {
case 'N':
dy = 1;
break;
case 'E':
dx = 1;
break;
case 'S':
dy = -1;
break;
case 'W':
dx = -1;
break;
}
for (i64 i = 0; i < abs(delta); ++i) {
++t;
x += dx;
y += dy;
if (m.find({x, y}) != m.end()) {
ans = min(ans, t - m[{x, y}]);
}
m[{x, y}] = t;
}
}
if (ans == MAX<i64>)
cout << "-1\n";
else
cout << ans << '\n';
}
int main() { // {{{
cin.tie(nullptr)->sync_with_stdio(false);
cin.exceptions(cin.failbit);
#define PROBLEM_NAME "mowing"
#ifdef LOCAL
freopen("io/" PROBLEM_NAME ".in", "r", stdin);
freopen("io/" PROBLEM_NAME ".out", "w", stdout);
#else
freopen(PROBLEM_NAME ".in", "r", stdin);
freopen(PROBLEM_NAME ".out", "w", stdout);
#endif
solve();
return 0;
}
// }}}