61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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typedef long long LL;
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int ccw(int x1, int y1, int x2, int y2, int x3, int y3) {
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LL s = (LL) (x2 - x1) * (LL) (y3 - y1) - (LL) (y2 - y1) * (LL) (x3 - x1);
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if (s > 0) return 1;
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if (s < 0) return -1;
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return 0;
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}
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int compare_leq(int x1, int y1, int x2, int y2) {
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if (x1 == x2) {
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return y1 <= y2;
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}
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return x1 <= x2;
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}
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int isIntersect(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4) {
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int d1 = ccw(x1, y1, x2, y2, x3, y3);
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int d2 = ccw(x1, y1, x2, y2, x4, y4);
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int d3 = ccw(x3, y3, x4, y4, x1, y1);
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int d4 = ccw(x3, y3, x4, y4, x2, y2);
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int c1 = d1 * d2;
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int c2 = d3 * d4;
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if (c1 == 0 && c2 == 0) {
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if (compare_leq(x2, y2, x1, y1)) {
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int temp = x1;
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x1 = x2;
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x2 = temp;
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temp = y1;
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y1 = y2;
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y2 = temp;
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}
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if (compare_leq(x4, y4, x3, y3)) {
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int temp = x3;
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x3 = x4;
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x4 = temp;
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temp = y3;
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y3 = y4;
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y4 = temp;
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}
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return (compare_leq(x1, y1, x4, y4) &&
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compare_leq(x3, y3, x2, y2));
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}
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return c1 <= 0 && c2 <= 0;
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}
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int main() {
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int x1, y1, x2, y2;
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int x3, y3, x4, y4;
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scanf("%d %d %d %d", &x1, &y1, &x2, &y2);
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scanf("%d %d %d %d", &x3, &y3, &x4, &y4);
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printf("%d\n", isIntersect(x1, y1, x2, y2, x3, y3, x4, y4));
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return 0;
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} |