48 lines
1.2 KiB
C++
48 lines
1.2 KiB
C++
#include <stdio.h>
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// 创建一个栈，拿到一个数，与栈顶比较，如果比栈顶小，压栈（正在波峰向波谷下降）
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// 比栈顶大，弹栈并计数；和栈顶相同，计数并且压入。
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struct NumberNode {
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int data;
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int count;
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};
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long long totalPairs;
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NumberNode powers[500010];
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int main() {
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int len = 1;
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int N;
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int input;
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totalPairs = 0;
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powers[0].data = 0;
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powers[0].count = 0;
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scanf("%d", &N);
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scanf("%d", &powers[1].data);
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powers[1].count = 1;
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N--;
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for (int i = 0; i < N; i++) {
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scanf("%d", &input);
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while (len != 0 && powers[len].data < input) {
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totalPairs += powers[len].count;
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len--;
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}
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if (len == 0 ) {
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powers[1].data = input;
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powers[1].count = 1;
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len = 1;
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} else {
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if (powers[len].data == input) {
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totalPairs += powers[len].count + (len > 1);
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powers[len].count++;
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}
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else {
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totalPairs += 1;
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powers[++len] = NumberNode {input, 1};
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}
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}
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}
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printf("%lld", totalPairs);
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return 0;
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} |