#include <cstdio>
#include <algorithm>
#include <cinttypes>
typedef long long ll;
#define MAXN 1000100
int reverse[MAXN];
int N;
int main() {
scanf("%d", &N);
int v;
for (int i = 0; i < N; ++i) {
scanf("%d", &v);
reverse[v] = i;
}
ll res = 1;
int maxpos = reverse[N];
int minpos = reverse[N];
int cval = N;
for (int i = N-1; i > 0; i--) {
int len = N + 1 - i;
if ((N - i) & 1) {
cval -= 1;
maxpos = std::max(maxpos, reverse[cval]);
minpos = std::min(minpos, reverse[cval]);
}
int min = std::max(0, maxpos - (len-1));
int max = std::min(N-1, minpos + (len-1));
res += std::max(max - min - len + 2, 0);
}
printf("%d %" PRId64 "\n", 2 * N + 1, res);
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 | #include <cstdio> #include <algorithm> #include <cinttypes> typedef long long ll; #define MAXN 1000100 int reverse[MAXN]; int N; int main() { scanf("%d", &N); int v; for (int i = 0; i < N; ++i) { scanf("%d", &v); reverse[v] = i; } ll res = 1; int maxpos = reverse[N]; int minpos = reverse[N]; int cval = N; for (int i = N-1; i > 0; i--) { int len = N + 1 - i; if ((N - i) & 1) { cval -= 1; maxpos = std::max(maxpos, reverse[cval]); minpos = std::min(minpos, reverse[cval]); } int min = std::max(0, maxpos - (len-1)); int max = std::min(N-1, minpos + (len-1)); res += std::max(max - min - len + 2, 0); } printf("%d %" PRId64 "\n", 2 * N + 1, res); return 0; } |
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