当我们用启动R安装一些R包的时候 提示: Warning: unable to access index for repository https://mirrors.eliteu.cn/CRAN/src/contrib: cannot open URL 'https://mirrors.eliteu.cn/CRAN/src/contrib/PACKAGES' Warning message: package 'RPMM' is not available (for R version 3.6.
106. The equation time limit per test: 0.25 sec. memory limit per test: 4096 KB There is an equation ax + by + c = 0. Given a,b,c,x1,x2,y1,y2 you must determine, how many integer roots of this equation are satisfy to the following conditions : x1<=x<